Electronmagnetohydrodynamic response of a plasma to an external current pulse

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872009· OSTI ID:280153

Zhou, H B; Papadopoulos, K; Sharma, A S ^[1]; Chang, C L ^[2]

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1. University of Maryland, College Park, Maryland 20742 (United States)
2. Science Applications International Corp., McLean, Virginia 22101 (United States)

In this paper we examine the dynamic response of a magnetoplasma to an external time-dependent current source in the context of electronmagnetohydrodynamics (EMHD). A combined analytic and numerical technique is developed to address this problem. The set of cold electron plasma and Maxwell{close_quote}s equations are first solved analytically in the ({bold k},{omega}) space. Inverse Laplace and three-dimensional complex Fast Fourier Transform techniques are used subsequently to numerically transform the radiation fields and plasma currents from the ({bold k},{omega}) space to the ({bold r},{ital t}) space. The results show that the electron plasma responds to a time-varying current source imposed across the magnetic field by exciting whistler/helicon waves and forming an expanding local current loop, driven by field-aligned plasma currents. The current loop consists of two antiparallel field-aligned current channels concentrated at the ends of the imposed current and a cross-field Hall current region connecting these channels. The characteristics of the current closure region are determined by the background plasma density, the magnetic field, and the time scale of the current source. The results are applied to the ionospheric generation of extremely low-frequency (ELF) and very low-frequency (VLF) radiation using amplitude modulated high-frequency heating. It is found that contrary to previous suggestions the dominant radiating moment of the ELF/VLF ionospheric source is an equivalent horizontal magnetic dipole. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 280153
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COLD PLASMA
DIELECTRIC PROPERTIES
ELECTROMAGNETIC FIELDS
ELECTRON GAS
FOURIER TRANSFORMATION
HELICON WAVES
IONOSPHERE
MAGNETOPAUSE
MAGNETOPLASMA
MAXWELL EQUATIONS
TRANSIENTS
WHISTLER INSTABILITY