Sheath dynamics of electrodes stepped to large negative potentials

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860513· OSTI ID:6817018

Calder, A C; Hulbert, G W; Laframboise, J G ^[1]

---

1. Department of Physics and Astronomy, York University, North York, Ontario M3J 1P3 (Canada)

Results are presented of particle simulations of the time-dependent behavior of the plasma sheath surrounding an electrode whose potential is abruptly changed from 0 to some negative value. The surrounding plasma is assumed isotropic and collisionless, and the electrode is a sphere or infinite cylinder. Potential steps up to [minus]1000[ital kT][sub [ital e]]/[ital e] are considered. The time histories and frequency spectra of sheath and plasma oscillations initiated by the potential step are studied. The energy in sheath oscillations (frequency [lt][omega][sub [ital p]]) escapes by nonlinear coupling to plasma oscillations (frequency [omega][sub [ital p]]). The time scale for sheath--plasma coupling depends strongly on the ion-to-electron mass ratio. Both linear and nonlinear ion acoustic waves are excited by the response to the potential step. Near a small (radius 1[lambda][sub D]) cylindrical electrode, trapped ions are shown to make an important contribution to the sheath ion density. The height of the transient peak in collected current for a cylindrical electrode displays strong dependence on the ion-to-electron temperature ratio, for sufficiently large potential steps.

• OSTI ID: 6817018
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:3; ISSN PFBPEI; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700350* -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
COLLISIONLESS PLASMA
ELECTRODES
OSCILLATIONS
PLASMA
PLASMA SHEATH
PLASMA SIMULATION
PLASMA WAVES
POTENTIALS
SIMULATION
TEMPERATURE DEPENDENCE