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CPP-IPR Seminars

CPP-IPR Seminar - PDF Talk

Title: Study of double layers in a multi-component plasma

Speaker: Ms. Dharitree Dutta, Doctoral Candidate, Gauhati University

Date, time and Venue: June 24, 2019 (Monday) Time: 3.00 pm CPP-IPR, Seminar Hall

Double layers have been found in a wide variety of plasmas from laboratory to space and have been considered as one of the major acceleration mechanism associated with different phenomena occurring in nature. It consists of two thin adjacent regions of excess space charge, which give rise to a potential drop across the layers. The planetary magnetosphere, heliosphere, the Van Allen Radiation belt, and the ionosphere are few examples of the hosts of double layers in the space. Because of its growing interests, theoretical and numerical works on the formation and the properties of double layers in the presence of suprathermal particles have been done earlier. On the other hand, plasma in general, may contain additional positive and (or) negative ions as well as dust particles besides the electron and positive ion and thus forms the multicomponent plasma. The aim of the proposed work is to study the formation, and characteristics of double layers in a Helicon Plasma Device in the presence of different electronegative gas mixtures (i.e., O2,Ar;  Ar,H2) through numerical simulation. The work has scope of applications in the designing of space propulsion engines such as helicon double layer thrusters.


CPP-IPR Seminar - PDF Talk

Title: Role of Sheath in Communication Blackout of Space Vehicle Re-entry

Speaker: Dr. Sayan Adhikari, Post Doctoral Fellow

Date, time and Venue: May 24, 2019 (Friday) Time: 3.00 pm CPP-IPR, VC Room

Communication blackout refers to the scenario when a spacecraft or module loses all of its communication with the Earth while reentering the Earth’s atmosphere at hypersonic speed. The blackout occurs due to the envelope of ionized air (plasma) around the spacecraft, created by the heat from the compression of the atmosphere. During the blackout, the radio waves used for communication between ground stations and satellites are attenuated and/or reflected by the plasma layer. The population of electrons near the antenna is the main reason behind this blackout. The plasma layer usually has an electron number density of 1017 to 1020 m-3. If the frequency at which the electrons oscillate is greater than the frequency of radio wave transmission, it results in reflection of the radio waves. The plasma frequency is directly proportional to the square root of the electron density of the plasma layer. Therefore, reducing electron density will certainly help in bringing down the plasma frequency. Eventually, it will help to reduce the blackout period. There are electrostatic and magnetized mitigation schemes, which provide a possibility for communication during radio blackout. The present study has attempted to explore the possibility of such mitigation schemes. The results suggest that magnetized mitigation schemes have more control over electron dynamics and capable of more power optimization.

In the next phase, exact environmental factors will be incorporated in the modeling to provide optimized parameters for different configurations of mitigation.


CPP-IPR Seminar - PDF Talk

Title: Wave Propagation in Dusty Plasma System

Speaker: Ms. Rinku Mishra, Doctoral Candidate

Date, time and Venue: May 15, 2019 (Wednesday) Time: 3.00 pm CPP-IPR, VC Room

Study of plasma waves is prevalent to understand different types of linear and non-linear plasma instabilities and energy transport. The collective behavior of plasma is very complex in nature, since it depends on the interaction of electrons and ions. Addition of dust into the plasma makes it more difficult to comprehend. The dust particles act as a source or sink for the electrons and ions making them non-neutral in nature. The coupling of charged particles with the electric or magnetic field in electron-ion plasma often leads to excitation of the various wave in a given plasma system. The presence of dust particles as an additional species introduces new wave modes and also modifies the existing ones. Considering dusty plasma to be infinitely continuous, several studies have been carried out to analyze the wave phenomena in a dusty plasma. Although, it is obvious that bounded or finite plasma always gives the realistic information. In case of bounded plasmas, apart from the electrostatic and electromagnetic plasma waves, surface wave also plays an important role. The surface wave is defined as the wave whose maximum energy is concentrated at the interface separating two media of different dielectric permittivity and shows the evanescent behavior on both sides of the interface. The dispersive property of plasma surface waves is mainly defined by the boundary conditions such as continuity of electric and magnetic field components along the sharp interface. However, the existence of plasma surface wave necessitates a sharp boundary. It has wide range of applications in industrial and laboratory environment which attracts various researchers to this field. Some of the important applications of plasma surface wave include plasma electronics, plasma antenna, plasma production, plasmonics devices, and particle heating by surface wave propagation in fusion.

The present topic of talk aimed to discuss the propagation of electrostatic waves namely the surface wave and volume waves in bounded and unbounded media respectively in dusty plasma. The dust charge fluctuation has been incorporated to study wave properties of the volume waves in both linear and non-linear regimes. The significant findings obtained through the studies are also highlighted.


CPP-IPR Seminar - PDF Talk

Title: Development and studies of a coaxial pulsed plasma accelerator

Speaker: Mr. Suramoni Borthakur, Doctoral Candidate

Date, time and Venue: May 15, 2019 (Wednesday) Time: 4.00 pm CPP-IPR, VC Room

A Pulsed Plasma Accelerator (PPA) system is a pulsed plasma device that produces a high density-high energy plasma stream with a very high velocity. The pulsed nature of the plasma has the advantage of achieving a very high energy density for a short duration, practically which is difficult to be produced in a continuous plasma device. When a pulsed power is applied across the two coaxial electrode assembly of the plasma system, the high voltage pulse forms plasma of the existing gas. The impulse high current produces a high magnetic field that interacts with the plasma sheath current density to provide the Lorentz thrust. This thrust gives the necessary acceleration to the plasma stream which can be used for many fruitful purposes, including matters relevant to fusion science. Such a device essentially has two main segments, one is a dedicated pulsed power source and the other is the plasma system. In general, the conventional pulsed plasma device has a discharge duration in the range of few tens of microseconds. But a modified form called the quasi-steady type plasma accelerators can have a much longer plasma life in the range of few hundreds of microseconds [1]. The difference in the time and energy factors greatly modifies the subsequent plasma characteristic, flow dynamics and plasma material interaction effects. Such a longer duration pulse demands some considerations in designing the circuit as well as in the selection of the components of Pulsed Power System [2]. Along with it, the plasma system also requires some pre-estimation and analysis of the plasma flow in the coaxial electrode system. All these things were brought into consideration while developing the PPA. Once installed, the next important activity was to ascertain the important parameters of the plasma like, plasma density, electron temperature, beam structure, stream velocity and energy density of the plasma [3]. Finally, an attempt was made to study plasma matter interaction using the plasma stream on material targets. The above mentioned development work will be presented in the presentation. Further, this device has the scope for exploring its performance for deposition purpose. Also, the theoretical work carried for understanding the plasma flow can be studied under the influence of magnetic field.


CPP-IPR Seminar - PDF Talk

Title: Inertial Electrostatic Confinement device and its application

Speaker: Mr. Neelanjan Buzarbaruah

Date, time and Venue: March 1, 2019 (Friday) Time: 3.45 pm CPP-IPR, Seminar Hall

Inertial electrostatic confinement (IEC) is a fusion concept that delivers fusion composites like neutrons, protons, and X-rays from a compact, low cost, and simple device. Seeing such multiple characteristics this confinement approach has been utilized for various non-electrical near-term applications prominently for neutron activation analysis (NAA). The other areas where it has been extensively used include land mine detection, neutron radiography, clandestine material detection at air and seaports, plasma space propulsion, subcritical fusion-fission hybrid reactors, tunable X-ray sources, boron neutron capture therapy (BNCT), medical isotope production, positron emission tomography (PET), ion thrusters etc. Thus, such cost-effective portable sources based on the principle of IEC provides a wider dimension of fusion-based applications. In India, CPP-IPR is the first institute to develop table-top IEC fusion devices (spherical and cylindrical) that demonstrate the 2.45 MeV neutrons by fusing deuterons (D-D). In such a device an HV (~ tens of kV) is applied to the cathode grid for the gas breakdown, the ions produced in the discharge oscillates in the negative potential well and overcomes the Coulomb barrier to fuse and produce neutrons. The signature of the D-D fusion neutrons emitted from the IEC device has been sensed using a number of detectors and it has been reported that presently the device is able to produce 106 n sec-1.

In order to increase the neutron production rate (NPR) from the cylindrical IEC device a work plan has been proposed that addresses some of the governing issues in the device such as improvement/increase of ion density, improved diagnostics for studying the fusion reaction regimes, application of magnetic fields for studying the confinement of ions and study on ion material interaction. The details of the proposed plan and work will be discussed during the talk.


CPP-IPR Seminar - PDF Talk

Title: Experimental Studies of Helicon Plasma in Electronegative Gases

Speaker: Mr. Narayan Sharma

Date, time and Venue: March 1, 2019 (Friday) Time: 3.00 pm CPP-IPR, Seminar Hall

The name Helicon Plasma Source (HeliPS) comes from the Helicon waves which are low frequency electromagnetic waves that propagate in the presence of magnetic fields. The ability of helicon discharge to produce higher plasma density and also less contamination due to the presence of antenna outside the chamber makes helicon plasma source more suitable for higher negative ion density. Considering these advantages of helicon discharge, a Helicon Plasma Source (HeliPS) is designed and developed for production and experiment of negative ions as well as the study of ion-ion plasma using electronegative gases such as hydrogen and oxygen. After design and development of the system, the characterization is done and the transition to helicon mode is established by various experiments. Experiments on negative ions in HeliPS are done by using hydrogen and oxygen gases. From the comparison of I-V curves at the different cases, the condition that favours the formation of ion-ion plasma in HeliPS is studied. Using uniform plasma model of propagation of electromagnetic waves in cylindrically bounded plasma, the collisional power deposition mechanism relevant to helicon discharge in HeliPS considering the realistic antenna structure is computed.

Although negative oxygen and hydrogen ions are produced successfully in HeliPS, there is scope for further improvement of negative ion density which at present is of the order of 109-10 cm-3. Proposed future work plan is to increase the negative ion density by using a gas mixture of argon and hydrogen & also argon and oxygen. Another proposed experiment is the extraction of ions by using grid assembly in the region between the expansion and extraction chambers of HeliPS. The Faraday cup placed beyond the extractor grid assembly will measure the extracted ion currents.


Thesis Pre-submission Talk

Title: Studies on dust containing hydrogen plasma in a multidipole device

Speaker: Mrs. Deiji Kalita

Date, time and Venue: January 30, 2019 (Wednesday) Time: 11.00 am CPP-IPR, Seminar Hall

Abstract: Dust formation and its charging play a crucial role in plasma processing devices and in fusion devices where magnetic fields are often used. The behavior of plasmas in a magnetic field is one of the interesting and essential topics in plasma physics. The role of magnetic field in various sophisticated plasma fusion devices is to confine the plasma elements. The influence of charged dust particulates on the plasma environment alters the transport of ions and electrons due to Lorentz force. The experiments are performed in the dusty plasma device where plasma is created by the hot cathode filament discharge technique. The plasma is confined by a full lined cusp magnetic field cage. To observe the effect of magnetic field on plasma parameters and dust charge, a permanent magnet having magnetic field strength 1.2 kG is placed inside the plasma chamber. The plasma parameters are measured axially at different distance from the magnet with the help of a cylindrical Langmuir probe. To study the effect on dust charging in presence of magnetic field, tungsten dust particles having (4 – 6) micron are used. The experimental work presented in the thesis includes the studies of the effect of external magnetic field (in presence/absence of) on different plasma parameters and particle charging. The different plasma parameters like electron density, ion density, electron temperature; electron energy probability function (EEPF), plasma oscillations for various dust densities are mainly investigated. The basic understanding to the study of electron energy distribution function (EEDF) is important for examining the different plasma parameters to optimize the plasma processes used for various applications. For the formation of transport barriers, cross-field diffusion coefficients and plasma–substrate interactions at the magnetized plasma, a clear understanding of EEDF is very necessary. The detail study on electron energy probability function (EEPF) is explained for hydrogen plasma in presence of magnetic field and dust grains at different conditions. The cold and high energetic electron densities, temperatures at different dust densities are evaluated from EEPF under the influence of magnetic field. Additionally, plasma oscillations for different dust densities and their effect with change in magnetic field strength are summarized at the end.


Thesis Pre-submission Talk

Title: Study on Plasma Surface Wave and Interaction of Dust Acoustic Mode with Dust Void

Speaker: Ms. Rinku Mishra

Date, time and Venue: 6th December 2018 (Thursday) Time: 3.00 pm CPP-IPR, Seminar Hall

Abstract: Plasma waves are very much prevalent to understand different types of linear and non-linear plasma instabilities and energy transport. Bounded or finite plasma medium is always known to give the realistic information about the wave properties of plasma. When we talk about bounded plasmas, apart from the electrostatic and electromagnetic plasma waves, plasma surface wave also plays an important role. However, the existence of plasma surface wave necessitates having a sharp boundary. Its wide range of applications in industrial and laboratory environment attracts various researchers to this field. Some of the important applications of plasma surface wave include plasma electronics, plasma antenna, plasma production, plasmonics devices, and particle heating by surface wave propagation in fusion. This thesis aims to investigate the propagation of both surface wave and volume waves with the inclusion of dust charge fluctuation under different situations in dusty plasma. A significant part of it has also discussed the interaction of dust acoustic wave with dust void mode. Theory and computation methodology propounded in this thesis is expected to have important industrial applications.


Thesis Pre-submission Talk - Talk-I

Title: DevelopMent Of A neutron source based on the inertial electrostatic confinement fusion scheme and its applications

Speaker: Mr. N. Buzarbaruah

Date, time and Venue: 26th November 2018 (Monday) Time: 3.00 pm CPP-IPR, Seminar Hall

Abstract: Compact and portable fusion neutron sources have high demand in the society compared for its use in various near-term applications. Some of the compact fusion sources are D-T accelerators, Z-pinch, Inertial Electrostatic Confinement (IEC) Fusion, Dense Plasma Focus (DPF) etc. Compared to other sources, IEC looks more attractive because of the operational simplicity, multifunctional usage, and cost-effectiveness. It is noteworthy to mention that by burning advanced fuels such as D-D (deuterium - deuterium) and D-T (deuterium - tritium), the device produces neutrons typically of the order of 107 - 108 n/sec and 109 - 1011 n/sec in steady state and pulsed modes, respectively. The produced neutrons can be exploited for different areas such as material science, biology, medicine, security, and industrial engineering. The IEC scheme relies on the trapping of deuterons within a purely electrostatic field that is appeared in between the central grid (cathode) and vacuum vessel (anode). On application of negative potential (-50 to -100 kV) to the cathode grid, the deuterons accelerate to the central region and, subsequently, oscillate across the grid to produce fusion at the core. This thesis work presents the design, fabrication, installation, and operation of the neutron source based on IEC Fusion scheme. The first chapter discusses its origin and principle of operation. The second chapter deals with the designing of the steady state volumetric neutron source that can produce neutrons of the order 106 to 108 D-D n/sec. The designing aspect considered some basic theoretical assumptions and computational tools to ascertain the ion trajectories inside the electrostatic field of the device. After fixing the device parameters and fabricating the same, the device has been installed with a host of supporting units and diagnostics that is presented in the third chapter. The fourth chapter highlights about the production of deuterium plasma inside the IEC device. The characteristic behaviour of the hot and cold cathode discharges using suitable diagnostics such as Langmuir probe and emission spectroscopy are also discussed in the chapter. On application of high negative voltage (~ 80 kV) to the cathode, the ions in the plasma are accelerated towards the cathode and recirculates. At optimum condition the deuterons fuse to produce neutrons that are detected by suitable neutron diagnostics discussed in chapter five. After the successful demonstration of neutrons, this maiden device at CPP-IPR successfully demonstrated the use of the neutrons for explosive detection. A detailed discussion on the design, fabrication and realization of the IEC device would be presented in the talk.


Thesis Pre-submission Talk - Talk-II

Title: DEVELOPMENT, STUDIES AND APPLICATION OF PULSED PLASMA ACCELERATOR

Speaker: Mr. S Borthakur

Date, time and Venue: 26th November 2018 (Monday) Time: 3.00 pm CPP-IPR, Seminar Hall

Abstract: A coaxial pulsed plasma accelerator is developed at CPP-IPR, powered by a 200 kJ Pulsed Power System with a peak discharge current of 100 kA for a pulse duration of 0.5 ms. The device can produce high density, high velocity plasma stream and can be utilised to study and simulate heat flux and Plasma Matter Interaction (PMI) related issues of tokamak plasma. Basically, the device consists of a coaxial electrode assembly housed inside a vacuum chamber. The basic design concept for relatively longer duration steady plasma stream production from plasma accelerator is taken from Morozov's theory. To sustain the plasma stream, a continuous supply of gas in between the electrodes is required during pulsing which is done by an electromagnetically actuated Gas Injection Valve (GIV). The plasma thus produced has been characterized using different diagnostics. Triple Langmuir probe (TLP) is used to measure the plasma density and electron temperature and found to be ~ 1021/m3 and ~ 24 eV respectively for nitrogen plasma. Double plate probe is used to measure the plasma stream velocity and found to be few tens of km/s. The energy density of the plasma during its impact on material surface is measured using a calorimeter and found to be of few hundreds of kJ/m2. As an initial test, nitrogen plasma beam is allowed to impact on SS304 surface and the effects are analysed. Further the observed properties of plasma beam show its potentiality for important results in the field of Plasma Matter Interaction (PMI). In this thesis, the development of a PPA along with a dedicated PPS, characterisation of the plasma produced and some preliminary PMI studies have been presented.


Thesis Pre-submission Talks - Talk-I

Title: A study on particle drifts across a magnetic filter and negative ions

Speaker: Parismita Hazarika

Date, time and Venue: 9th November 2018 (Friday); Time: 3.00 pm CPP-IPR, Seminar Hall

Abstract: The present thesis work mainly deals with the study of particle drift across a magnetic filter in different source and magnetic filter field configurations. This study has importance in volume negative ion sources, where optimization of the negative ion formation parameters require a proper study of the transverse magnetic filter field and the filter field region. The first objective of this thesis is to study the effect of electrostatic trapping of magnetized electrons in the filter region which is done by application of a negative potential to the TMF channels with reference to the ground. This study helps us to understand the role played by the trapped electrons in altering the plasma parameters in the source and target region and thereby on the plasma transport processes. The second objective of this thesis is to study the effect of density, temperature and magnetic field dependent charged particle drift on cross field plasma transport. To measure negative ion density, a proper diagnostic system is required. So, the third objective of the thesis deals with setting-up of the laser photo-detachment diagnostic and measurement of negative ion density. This diagnostic system consists of a pulsed laser having a diameter of a few mm of suitable wavelength and energy. Different filament materials are also used to study their influence on different plasma parameters such as density, temperature, plasma potential etc. and negative ion production.


Thesis Pre-submission Talks - Talk-II

Title: Development of Helicon Plasma Source and a Study of Ion-Ion Plasma

Speaker: Narayan Sharma

Date, time and Venue: 9th November 2018 (Friday); Time: 3.00 pm CPP-IPR, Seminar Hall

Abstract: The name Helicon Plasma Source (HeliPS) used for our experimental set-up is derived from Helicon waves. They are the low frequency electromagnetic waves that propagate in the presence of magnetic fields. Helicon waves are right handed circularly polarized electromagnetic waves which propagate in the presence of magnetic fields. The ability of helicon discharge to produce higher plasma density and less contamination makes helicon plasma source more suitable for higher negative ion density. Considering these advantages of helicon discharge, a Helicon Plasma Source (HeliPS) is designed and developed for production and experiment of negative ions as well as the study of ion-ion plasma using electro-negative gases such as Hydrogen and Oxygen. After design and development of the system, the characterization is done and the transition to helicon mode is established by various experiments. Experiments on negative ions in HeliPS are done by using Hydrogen and Oxygen gases. From the comparison of I-V curves at the different cases, the condition that favours the formation of ion-ion plasma in HeliPS is studied. Using uniform plasma model of propagation of electromagnetic waves in cylindrically bounded plasma, the collisional power deposition mechanism relevant to helicon discharge in HeliPS considering the realistic antenna structure is computed. The talk discusses on the design, development, and characterization of HeliPS as well as the production of negative ions using Hydrogen and Oxygen gases.


CPP-IPR Seminar - PDF Talk

Title:

Speaker: Dr. Gopikishan S

Date, time and Venue: 16/08/2018 (16th August); Time: 3.00 pmCPP-IPR, Seminar Hall

Pollution of water by heavy metals and microorganisms are paid attention due to their toxicity to human life. Silver has long been known to exhibit a strong toxicity to a wide range of microorganisms, but not harmful to human. It is reported that antibacterial properties of the silver is size dependent, where smaller nanoparticles appeared to have enhanced antibacterial activity [1]. We have carried out size controlled synthesis of silver nanoparticles utilizing the existing CPP-IPR nanoparticle reactor [2], which however failed to produce appropriate sizes while using micron sized silver particles alone. However, average size of the nanoparticles was seen to decrease to just few tens of nanometers, while methane was co-injected along with the silver micron particles. The average size of the silver nanoparticles was estimated by Scherrer formula whereas surface morphology examined by a scanning electron microscope (SEM). Along with Ag-C we also synthesized size controlled nanoparticles of carbon encapsulated iron crystallites. Very recently, extensive measurements were initiated on estimation of the absorption properties of the Ag-C nanocomposites and carbon encapsulated magnetic nanoparticles (CEMN) for the following two metals: chromium and arsenic, at NCCCM, BARC Hyderabad, using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Some of the CEMN samples were further functionalized by oxidative reactions during the same single step synthesis process and impressive absorption capacity 10.027mg/g is observed, while the Cr concentration was 5.0 mg/L and 400mg/L of OCEMN absorbent. The removal capacity is gradually increased as a function Cr concentration; it is a positive sign for future course of work. For future work, CEMN will be functionalized with nitrogen which may enhance absorption even better than surface oxidation. Anti-bacterial properties of the nanocomposites will be also studied. I am also associated with PSI studies carried out in the CIMPLE-PSI device and involved with the maintenance of the devices.


CPP-IPR Seminar - Thesis Pre-submission Talk

Title: Approaches to Study Ion Dynamics in Magnetized Plasma Sheath and its Potential Applications

Speaker: Mr. Sayan Adhikari

Date, time and Venue: 7th May 2018 (Monday)

The interface between a surface and a plasma is quite a complicated area in plasma physics. A single approach is never adequate to solve all the mysteries. While the fluid analysis does an excellent job explaining the gross behavior of plasma, it fails to explain some of the physical events that take place in the system. Kinetic methods are convenient in these situations. Studies reveal that the particle distribution in front of a surface deviates from Maxwellian leading to a different scenario. In the presence of magnetic field, it becomes more difficult to model using fluid approach. Hence, there are several unexplored areas in the field, which calls for an investigation. The works presented here use both the Fluid1 and Kinetic2 approaches to understand the ion dynamics in detail with the aim to investigate the physical processes that govern them in the sheath region. Asummary of the two works is given below: The first work deals with the influence of the forces that control the ion dynamics inside a magnetized plasma sheath under collisionless condition using fluid approach. The study becomes essential in a context, where the magnetic field lines intersect the surface obliquely. The study reports that the electric field starts to disperse with the field inclination angle ?. As we bring down the value of ?, peak in ion density distribution starts to develop indicating deceleration of ions due to magnetic force towards the wall. In the second work, a bounded plasma is being simulated with a spatially generated source in the presence of an oblique magnetic field using kinetic Particle-In-Cell (PIC) technique. The study includes the theory of ion reflection in a magnetized source-collector sheath highlighting its impact on the sheath entry velocity of the ions. Additionally, the role of the sheath in Communication Blackout of space vehicle re-entry has also been discussed as a potential application in the area.


CPP-IPR Seminar - Thesis Pre-submission Talk

Title: Study of Edge Physics in Magnetized Plasma

Speaker: Mr. Sayan Adhikari

Date, time and Venue: Mar 20, Tuesday, 2018, 03.30 PM, at CPP-IPR Seminar Hall

Plasma has a profound influence on human life even before it was identified as a separate state of matter. From clinical to mechanical, it has given us countless possibilities to make our lives easier. Apart from celestial plasma, nearly all the laboratory plasmas involve surface interactions. The interaction process is a complex process. The high energetic ions from the bulk plasma are most likely to hit the surface, resulting in dislocation of the surface atoms. The process is characterized as sputtering. In due course of time, sputtering can lead to a situation where the atoms from the surface start coming out, leaving behind voids in the material. The situation is described as erosion. The sputtered atoms can get ionized and enter the bulk plasma resulting in a contamination. This brings some serious concern about the lifetime of the plasma as well as the material that contains it. The thesis aims to investigate the physical processes at the plasma edge, which lead to influence the edge transport, as well as the processes that determine the sputtering and erosion of materials.


CPP-IPR Seminar - Pre-final Registration Talk

Title: DEVELOPMENT AND STUDIES ON PULSED PLASMA ACCELERATOR AND APPLICATION OF THE PULSED PLASMA

Speaker: Mr. Suramoni Borthakur

Date, time and Venue: Dec 12, Tuesday, 2017, 03.30 PM, at CPP-IPR Seminar Hall

Abstract: A Pulsed Plasma Accelerator (PPA) facility has been designed and developed at CPP-IPR. The device is powered by a 200 kJ Pulsed Power System (PPS) developed in our laboratory. The plasma produced in the device has been characterized by various diagnostics like, Pin-hole imaging, Triple Langmuir Probe, Double Plate Probe and Calorimeter. The diagnostic results has given different parameters of the plasma such as plasma density, electron temperature, plasma stream velocity, heat content of the plasma stream etc. Presently we have started the plasma matter interaction in which few SS 304 samples has been exposed to the plasma stream. The results of the above work will be discussed in the presentation.


CPP-IPR Seminar

Title: Studies on wall conditioning for graphite and SS 304L wall materials

Speaker: Dr. Bharat Kakati, IPR, Gandhinagar

Date, time and Venue: April 12, Wednesday, 2017, 02.30 PM, at CPP-IPR Seminar Hall

Abstract: A systematic study on wall conditioning is carried out in an ultrahigh vacuum device with an objective to evaluate the optimum wall conditioning parameters for graphite and SS 304L wall materials. Higher gas loads of different impurities are observed with graphite than SS 304L wall. Recent experimental results show that for the removal of water impurity from SS 304L and graphite walls, the chamber walls should be baked at ? 2500C. Helium glow discharge cleaning (He-GDC) is found to be very effective for desorption of hydrogen impurities whereas Hydrogen (H) GDC is very effective for the desorption of carbon and oxygen impurities. The desorption of water impurities show almost similar behaviour in both H- and He-GDC. It is observed that the H- and He-GDC at elevated wall temperature is very effective for the desorption of wall impurities. The fuel retention on graphite wall during H-GDC is much higher as compared to He-GDC. Recent experimental results show that the fuel retention on walls can be reduced by performing the GDC at elevated wall temperature.


CPP-IPR Seminar

Title: Investigation of Magnetized Plasma Instabilities using Probes

Speaker: Dr. K.S.Ganesh Prasad, Shree Raghavendra Technical Services, Pvt. Ltd, Ahmedabad

Date, time and Venue: April 03, Monday, 2017, 03.30 PM, at CPP-IPR Seminar Hall

Abstract: Probes forms simple inexpensive diagnostic and has been explored for studying plasma instabilities like drift waves, Rayleigh Taylor instability etc. Great care has to be taken while interpreting data. Electronics associated with probe diagnostics should ensure good frequency response. This talks presents probe diagnostics preparation for analysis of plasma instability phenomena.


CPP-IPR PDF Review Talk:

Title: SYSTEM DEVELOPMENT AND EXPERIMENTS IN THE CIMPLE-PSI LABORATORY, CPP-IPR

Speaker: Dr. Ngangom Aomoa

Date, time and venue: March 20, 10.30 AM, CPP-IPR Seminar hall

ABSTRACT: In this talk I will summarize my developmental/research activities carried out as a Post Doctoral Fellow in the CPP-IPR CIMPLE-PSI laboratory in the last two years. An extensive characterization of the CPP-IPR High Heat Flux (HHF) device was carried out by optical emission spectroscopy and water calorimetry in that period, which will be presented here. Important results from a basic plasma surface interaction (PSI) experiment carried out in the same device will be also presented. Experiments will be described that led to the evolution of new segmented torch designs, that were later successfully operated under higher power/magnetic field conditions. Brief reports on the installation/ commissioning of the individual components of the CIMPLE-PSI device, including substrate holders, electromagnet, vacuum system etc. will be also presented. The integrated device was successfully commissioned, which even under restricted low power operation,produced helium ion fluxes of the order of 1024 m-2s-1 and heat flux in few megawatt/m2. I was also involved with plasma assisted synthesis of nanomaterials, where for the first time by a plasma method, we have recently synthesized encapsulated magnetic nanoparticles supposed to be best suitable for targeted drugs deliver applications and nano-tungsten, results from which also will be presented. The proposed plan of work for the next one year will be also discussed."


CPP-IPR Seminar:

Ph.D. Thesis Pre-submission Talk

Title: Collisional Effects in Multicomponent Plasma

Speaker: Rakesh Moulick

Date, time and venue: July 27, 03.00 PM, CPP-IPR Seminar Hall

Abstract: The effect of collision in plasma is always inevitable and leads to many phenomena of fundamental importance. The thesis is motivated by the presence of ion neutral collision and tries to investigate and analyze some beautiful occurrences due to the ion and neutral collision. The plasma environment is multicomponent in nature and involves the presence of dust and negative ions. The formation of sheath in such environment is widely discussed. The thesis starts with the discussion of the negative ion behavior under the collisional condition in the multicomponent environment. The interesting behavior observed here is that despite increasing the ion neutral collision, the negative ion behavior seems to be Boltzmann-like. Temperature has certainly an effect on the distribution. An attempt has been made to portray the charging of the dust particles under collisional environment. The velocity dependent collision frequency has been found to play some key role in plasma behavior. The formation of sheath in the ambience of dust and negative ion is found to be highly motivated by the presence of ion neutral collision. Moreover, various forces acting on the dust particles and their variation with the collision parameter is widely highlighted. Potential structure near a dust particle under collision environment is seen to have a dip to act as the zone of negative particle trapping and consequently affecting the process of grain charging.


CPP-IPR Colloquium

Title: Overview of facilities at UGC DAE CSR, Indore

Speaker: Dr. V. Ganesan, Centre Director, CSR, Indore

Date, time and venue: February 02, 2016, 11.00 AM, Seminar Hall, CPP-IPR, Sonapur 782 402


CPP-IPR Colloquium

Title: Suite of codes for SOL plasma and PSI modeling

Speaker: M. Warrier, Computational Analysis Division, BARC, Visakhapatnam, AP, India

Date, time and venue: December 07, 2015, 3.00 PM, CPP-IPR Seminar Room.

Abstract: The installation and usage of the following codes dealing with Scrape Off Layer (SOL) plasmas and Plasma Surface Interactions will be presented:
1. 1-D Fokker Planck collisional sheath solver which gives the ion and electron energy distributions throughout a collisional sheath. It considers ionization, charge exchange, dissociation and elastic collisions with neutrals.
2. ZEPHYR - 1D SOL model code. It solves the plasma Fluid Equations for continuity, momentum and electron and ion energy fluxes (source listing given in Culham Laboratory Report CLM-R234). The code was modified to Include a new numerical scheme COLSYS which is a collocation point method to solve two point boundary value problems. It provides the density, ion and electron temperatures and heat flux profiles along the SOL of a tokamak.
3. SMPIS-ELM - A suite of subroutines to handle physical and chemical sputtering, backscattering and 1-D transient heat transport in divertor materials. It can be used to study the effect of ELM trains on a divertor target.
4. A two point BARR model, which gives an analytical solution for heat flux on divertor plates. This model has compared favorably with 2D SOL modeling codes like B2-EIRENE.


Ph.D. Thesis Pre-submission Talk

Title: Collisional Effects in Multicomponent Plasma

Speaker: Rakesh Moulick, Senior Research Fellow

Centre of Plasma Physics - Institute for Plasma Research, Sonapur 782 402

Date, time and venue: October 30, Friday, 2015, 3.00 PM, CPP-IPR Seminar Room.

Abstract: The effect of collision in plasma is always inevitable and leads to many phenomena of fundamental importance. The thesis is motivated by the presence of ion neutral collision and tries to investigate and analyze some beautiful occurrences due to the ion and neutral collision. The plasma environment is multicomponent in nature and involves the presence of dust and negative ions. The formation of sheath in such environment is widely discussed and an attempt has been made to portray the charging of the dust particles under collisional environment. The velocity dependent collision frequency has been found to play some key role in plasma behavior. The formation of sheath in the ambience of dust and negative ion is found to be highly motivated by the presence of ion neutral collision. Moreover, various forces acting on the dust particles and their variation with the collision parameter is widely highlighted. Potential structure near a dust particle is seen to have a dip to act as the zone of negative particle trapping and consequently affecting the process of grain charging.

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