Effect of collisions, ionisation and non-extensivity on sheath formation in an electronegative warm plasma under electron emission from the wall
محورهای موضوعی : Journal of Theoretical and Applied Physics
Yetendra Jha
1
(Plasma Science and Technology Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, India.)
Mayank Kumar
2
(Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, India.)
Hitendra K. Malik
3
(Plasma Science and Technology Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, India.)
کلید واژه: Secondary electron emission, plasma-material interaction, Sheath thickness, electric potential,
چکیده مقاله :
The effect of collisions, ionisation and non-extensivity is studied numerically in an electronegative warm plasma associated with electron emission from the wall. Electrostatic potential, space charge density, net negative charge density and emitted electron beam density are plotted with the normalised distance to see the effects of aforesaid parameters The negative ion is described with fluid equations to see it’s effect of the mass ratio (negative ion to positive ion) on emitted electron beam density inside the sheath. The three types of electronegative plasma taken are CF_4, O_2 and C_60. The emitted beam electron density is more in number at the wall for higher collisional and ionisation case and less in higher mass ratio. For super-extensive case the emitted beam electrons is lesser than compared to the Boltzmann distributed electrons. The sheath thickness is found to be more in higher mass ratio, emitted beam electrons and super -extensive case while for higher collisional and ionisation case the sheath thickness is less.
