Stability of different plasma sheaths near a dielectric wall with secondary electron emission
Abstract
The linear theory stability of different collisionless plasma sheath structures, including the classic sheath, inverse sheath and spacecharge limited (SCL) sheath, is investigated as a typical eigenvalue problem. The three background plasma sheaths formed between a Maxwellian plasma source and a dielectric wall with a fully selfconsistent secondary electron emission condition are solved by recent developed 1D3V (onedimensional space and threedimensional velocities), steadystate, collisionless kinetic sheath model, within a wide range of Maxwellian plasma electron temperature T_{e}. Then, the eigenvalue equations of sheath plasma fluctuations through the three sheaths are numerically solved, and the corresponding damping and growth rates γ are found: (i) under the classic sheath structure (i.e. T_{e}<T_{ec} (the first threshold)), there are three damping solutions (i.e. γ_{1}, γ_{2} and γ_{3}, 0 > γ_{1} > γ_{2} > γ_{3}) for most cases, but there is only one growthrate solution γ when T_{e}\rArr T_{ec} due to the inhomogeneity of sheath being very weak; (ii) under the inverse sheath structure, which arises when T_{e}>T_{ec}, there are no background ions in the sheath so that the fluctuations are stable; (iii) under the SCL sheath conditions (i.e. T_{e}≥T_{eSCL}, the second threshold), the obvious ion streaming through the sheath region again emerges and the three damping solutions are again found.
 Publication:

Journal of Plasma Physics
 Pub Date:
 December 2019
 DOI:
 10.1017/S0022377819000862
 Bibcode:
 2019JPlPh..85f9009Q
 Keywords:

 plasma instabilities;
 plasma sheaths