TY - JOUR

T1 - Kinetic Theory of the Wall Sheath for Arbitrary Conditions in a Gas-Discharge Plasma

AU - Murillo, O.

AU - Mustafaev, A. S.

AU - Sukhomlinov, V. S.

PY - 2019/9/1

Y1 - 2019/9/1

N2 - Abstract: The self-consistent problem of the structure of a perturbed wall sheath in a dc gas-discharge plasma near a flat surface under negative potential relative to the plasma has been solved for an arbitrary relation between the Debye radius and the ion mean free path. The solution has been obtained without artificial separation of this layer into the quasi-neutral “presheath” and the wall sheath in which quasi-neutrality is violated substantially. The actual ion distribution function in the unperturbed plasma, the dependence of the charge-exchange cross section on the ion energy, and the nonzero electric field in the unperturbed plasma have been considered. It is shown that when the average electron energy is conserved the structure of the perturbed wall sheath weakly depends on the form of the electron distribution function. It has been established that the mean energy of ions in the unperturbed plasma substantially affects the structure of the quasi-neutral presheath as well as the structure of a part of the wall sheath in which quasi-neutrality is not observed even under the assumption that the mean electron energy is much higher than the mean energy of ions. The calculations of ion flow parameters and the structure of the perturbed wall sheath are in conformity with experimental data obtained by other authors, which could not be adequately interpreted earlier.

AB - Abstract: The self-consistent problem of the structure of a perturbed wall sheath in a dc gas-discharge plasma near a flat surface under negative potential relative to the plasma has been solved for an arbitrary relation between the Debye radius and the ion mean free path. The solution has been obtained without artificial separation of this layer into the quasi-neutral “presheath” and the wall sheath in which quasi-neutrality is violated substantially. The actual ion distribution function in the unperturbed plasma, the dependence of the charge-exchange cross section on the ion energy, and the nonzero electric field in the unperturbed plasma have been considered. It is shown that when the average electron energy is conserved the structure of the perturbed wall sheath weakly depends on the form of the electron distribution function. It has been established that the mean energy of ions in the unperturbed plasma substantially affects the structure of the quasi-neutral presheath as well as the structure of a part of the wall sheath in which quasi-neutrality is not observed even under the assumption that the mean electron energy is much higher than the mean energy of ions. The calculations of ion flow parameters and the structure of the perturbed wall sheath are in conformity with experimental data obtained by other authors, which could not be adequately interpreted earlier.

KW - Bohm criterion

KW - Boltzmann equation

KW - gas-discharge plasma

KW - wall sheath

KW - TRANSITION

KW - BOHM CRITERION

KW - PATCH ACTIVE PLASMA

KW - GLOW

UR - http://www.scopus.com/inward/record.url?scp=85073245120&partnerID=8YFLogxK

U2 - 10.1134/S106378421909010X

DO - 10.1134/S106378421909010X

M3 - Article

AN - SCOPUS:85073245120

VL - 64

SP - 1308

EP - 1318

JO - Technical Physics

JF - Technical Physics

SN - 1063-7842

IS - 9

ER -