Title: Tethered Capacitor Charge Mitigation in Electron Beam Experiments

Abstract

Energetic electron beams have been proposed for tracing magnetic field lines from the magnetosphere down to the ionosphere, in active experiments aimed at diagnosing mechanisms at play in the coupling between magnetosphere and ionosphere. It is recognized however that in the absence of an efficient mitigation technique, this approach would lead to unacceptably large spacecraft charging and positive potential buildup, which would result in environmental hazard for the spacecraft. This problem would be particularly acute in low density regions of the magnetosphere of interest in the study of magnetic field reconnection and substorm dynamics. A solution to this predicament could consist of creating a plasma contactor whereby a gas puff would be ionized, leading to the evacuation of positive charges and collection of cold electrons, thus compensating for the charges lost in the electron beam. A possible alternative is presented here, which consists of attaching a large passive conducting surface to the spacecraft, a “tethered capacitor”, from which negative charges would be drawn to compensate for those lost from the beam. This capacitor would then charge to a large positive potential, leaving the spacecraft and electron gun at a lower, acceptable positive potential. The tethered capacitor could have a relativelymore » small mass; consisting only of a thin conducting surface that would be “inflated” as a result of repulsive electrostatic forces. This charge mitigation concept, as applied to active electron beam experiments, is explored using three dimensional particle-in-cell (PIC) simulations from which scaling laws can be inferred for the spacecraft and tethered capacitor potentials under proposed electron beam operations.« less

Authors:

Marchand, Richard ^[1]; Delzanno, Gian Luca  ^[2]

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• Search DOE PAGES for ORCID "0000-0002-7030-2683"

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+ Show Author Affiliations

1. Univ. of Alberta, Edmonton, AB (Canada)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Thu Dec 13 00:00:00 EST 2018

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1558211

Report Number(s):

LA-UR-18-30554
Journal ID: ISSN 2296-987X

Grant/Contract Number:  

89233218CNA000001

Resource Type:

Accepted Manuscript

Journal Name:

Frontiers in Astronomy and Space Sciences

Additional Journal Information:

Journal Volume: 5; Journal ID: ISSN 2296-987X

Publisher:

Frontiers Research Foundation

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY