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Electrochemical Etching and Characterization of Sharp Field Emission Points for Electron Impact Ionization
Published on: July 12, 2016
Nonlocal electron kinetics in a planar inductive helium discharge
1Department of Physics, Korea Advanced Institute of Science and Technology, Taejon 305-701, South Korea.
Summary
Measurements in helium plasma revealed a bi-Maxwellian electron energy distribution function (EEDF) at low pressures. This indicates distinct electron groups, influenced by plasma conditions and electron interactions.
Area of Science:
- Plasma Physics
- Atomic and Molecular Physics
Background:
- Understanding electron behavior in plasmas is crucial for various applications.
- The electron energy distribution function (EEDF) dictates plasma properties.
- Helium, a non-Ramsauer gas, is used in this planar inductive plasma study.
Purpose of the Study:
- To measure the EEDF in a helium planar inductive plasma.
- To investigate factors influencing EEDF formation, particularly at low pressures.
- To calculate the electron energy diffusion coefficient using simulations.
Main Methods:
- Electron energy distribution function (EEDF) measurement using the ac superposition method.
- Helium pressure range: 10-100 mTorr.
- Two-dimensional simulation to calculate the electron energy diffusion coefficient.
Main Results:
- A bi-Maxwellian EEDF was observed at low helium pressures (< 20 mTorr).
- This bi-Maxwellian distribution features a distinct low-energy electron group.
- Factors contributing to the bi-Maxwellian EEDF include capacitive field effects, ambipolar potential, and low electron-electron collision frequency.
Conclusions:
- The bi-Maxwellian EEDF in helium plasma is influenced by electron cooling, heating rates, and confinement.
- Electron-electron collision frequency, estimated via total electron bounce frequency, plays a key role.
- The findings provide insights into electron dynamics in low-pressure inductive plasmas.
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