Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2012-03-01

Journal: PHYSICS OF PLASMAS

Included Journals: EI、SCIE

Volume: 19

Issue: 3

ISSN: 1070-664X

Abstract: A particle-in-cell simulation was employed to investigate the nature and physical cause of the nonlinear oscillation of electrons induced by a nanosecond pulse in rf capacitive hydrogen discharges. It was found that the applied nanosecond pulse converted the plasma quickly from the bi-Maxwellian equilibrium formed in the rf capacitive discharge into another temporal bi-Maxwellian equilibrium. When the applied electric field collapses within a few nanoseconds, the electric field arising from the space charge serves as a restoring force to generate a swift oscillation of the electrons. The energy stored in the plasma is converted gradually into the chemical energy during the electron periodic movement. It is also found that the rise-, plateau-, and fall-times of the applied pulse affect the evolution of the electron energy distribution. The collective electron oscillation has a repetition frequency approximately equal to the electron plasma frequency, independent of pulse rise-, plateau-, and fall-times. This oscillation of electrons induced by a nanosecond pulse can be used to generate highly excited vibrational states of hydrogen molecules, which are a necessary precursor for negative hydrogen ions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695121]