Kanesh Kumar Jayapalan

The effects of neutral gas heating on H mode transition and maintenance currents in a 13.56 MHz planar coil inductively coupled plasma reactor

The H mode transition and maintenance currents in a 13.56 MHz laboratory 6 turn planar coil inductively coupled plasma (ICP) reactor are simulated for low pressure argon discharge range of 0.02-0.3 mbar with neutral gas heating and at ambient temperature. An experimentally fitted 3D power evolution plot for 0.02 mbar argon pressure is also shown to visualize the effects of hysteresis in the system. Comparisons between simulation and experimental measurements show good agreement in the pressure range of 0.02-0.3 mbar for transition currents and 0.02-0.1 mbar for maintenance currents only when neutral gas heating is considered. This suggests that neutral gas heating plays a non-negligible role in determining the mode transition points of a rf ICP system.

Effect of neutral gas heating on the wave magnetic fields of a low pressure 13.56 MHz planar coil inductively coupled argon discharge

The axial and radial magnetic field profiles in a 13.56 MHz (radio frequency) laboratory 6 turn planar coil inductively coupled plasma reactor are simulated with the consideration of the effect of neutral gas heating. Spatially resolved electron densities, electron temperatures, and neutral gas temperatures were obtained for simulation using empirically fitted electron density and electron temperature and heuristically determined neutral gas temperature. Comparison between simulated results and measured fields indicates that neutral gas heating plays an important role in determining the skin depth of the magnetic fields.

Investigating the characteristics of a coplanar-coaxial atmospheric pressure dielectric barrier discharge jet in argon

Non-thermal atmospheric pressure plasma jet can easily be generated via a coplanar-coaxial dielectric (quartz tube) barrier discharge configuration driven by AC high voltage source at 11 kHz frequency in flowing argon gas. The plasma jet was characterized by its physical dimension, electrical and optical emission properties. It was found that smaller diameter of the quartz tube produced jets of shorter length. To generate a jet at maximum length for larger tube diameters, higher gas flow rate was required. Increasing the width of the active electrode also produced plasma jets of longer length. Current spikes superposed on the sinusoidal current waveforms were observed when the active electrode of shorter length was used. These spikes diminished when the width of the active electrode was increased to 15 mm. When the active and ground electrodes were inter-changed in position, no plasma jet was formed externally but upstreaming of the jet was observed. No discharge was ignited when the ground electrode was ...

Radio Frequency Planar Inductively Coupled Plasma: Fundamentals and Applications

This chapter examines some of the key fundamentals of planar radio frequency inductively coupled plasmas (or RF ICPs) including the various modes of operation, hysteresis between modes, power balance of the plasma operating states and dynamics of the source electromagnetic fields in the presence of plasma. These properties are discussed with the demonstration of several theoretical models. The characteristics and effects of neutral gas heating, as well as the technique of measurement of neutral gas temperature are also presented. The chapter is concluded with a discussion on the applications of RF planar ICPs and their development throughout the years.

Theoretical and experimental studies of a planar inductive coupled rf plasma source as the driver in simulator facility (ISTAPHM) of interactions of waves with the edge plasma on tokamaks

This research aims to design and build a planar inductive coupled RF plasma source device which is the driver of the simulator project (ISTAPHM) of the interactions between ICRF Antenna and Plasma on tokamak by using the AMPICP model. For this purpose, a theoretical derivation of the distribution of the RF magnetic field in the plasma-filled reactor chamber is presented. An experimental investigation of the field distributions is described and Langmuir measurements are developed numerically. A comparison of theory and experiment provides an evaluation of plasma parameters in the planar ICP reactor. The objective of this study is to characterize the plasma produced by the source alone. We present the results of the first analysis of the plasma characteristics (plasma density, electron temperature, electron-ion collision frequency, particle fluxes and their velocities, stochastic frequency, skin depth and electron energy distribution functions) as function of the operating parameters (injected power, neutral pressure and magnetic field) as measured with fixed and movable Langmuir probes. The plasma is currently produced only by the planar ICP. The exact goal of these experiments is that the produced plasma by external source can exist as a plasma representative of the edge of tokamaks.

Measurement of neutral gas temperature in a 13.56 MHz inductively coupled plasma

Measuring the temperature of neutrals in inductively coupled plasmas (ICP) is important as heating of neutral particles will influence plasma characteristics such as the spatial distributions of plasma density and electron temperature. Neutral gas temperatures were deduced using a non-invasive technique that combines gas actinometry, optical emission spectroscopy and simulation which is described here. Argon gas temperature in a 13.56 MHz ICP were found to fall within the range of 500 − 800 K for input power of 140 − 200 W and pressure of 0.05 − 0.2 mbar. Comparing spectrometers with 0.2 nm and 0.5 nm resolution, improved fitting sensitivity was observed for the 0.2 nm resolution.

Effect of neutral gas heating in argon radio frequency inductively coupled plasma

Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile.

Simulation and Experimental Study of a 13.56 MHz Planar Coil, Inductively Coupled Plasma Reactor

Hysteresis in a 13.56 MHz planar coil, inductively coupled plasma (ICP) reactor is modeled using the methods prescribed in El‐Fayoumi et al. [2] and Turner et al. [3]. The stable working points of the reactor are identified by determining the intersections between simulated absorbed electron power and electron loss power curves. From the plots, transition currents between stable working points are identified and compared with experimentally measured values. Study of hysteresis in ICPs provides better understanding of ICP formation which would be useful for reactor pressure and current optimization.