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Title: Future beam experiments in the magnetosphere with plasma contactors: The electron collection and ion emission routes

Experiments where a high-voltage electron beam emitted by a spacecraft in the low-density magnetosphere is used to probe the magnetospheric configuration could greatly enhance our understanding of the near-Earth environment. Their challenge, however, resides in the fact that the background magnetospheric plasma cannot provide a return current that balances the electron beam current without charging the spacecraft to such high potential that in practice prevents beam emission. In order to overcome this problem, a possible solution is based on the emission of a high-density contactor plasma by the spacecraft prior to and after the beam. In this paper, we perform particle-in-cell simulations to investigate the conditions under which a high-voltage electron beam can be emitted from a magnetospheric spacecraft, comparing two possible routes that rely on the high-density contactor plasma. The first is an “electron collection” route, where the contactor has lower current than the electron beam and is used with the goal of connecting to the background plasma and collecting magnetospheric electrons over a much larger area than that allowed by the spacecraft alone. The second is an “ion emission” route, where the contactor has higher current than the electron beam. Ion emission is then enabled over the largemore » quasi-spherical area of the contactor cloud, thus overcoming the space charge limits typical of ion beam emission. Finally, our results indicate that the ion emission route offers a pathway for performing beam experiments in the low-density magnetosphere, while the electron collection route is not viable because the contactor fails to draw a large neutralizing current from the background.« less
 [1] ;  [2] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Space Science Inst., Boulder, CO (United States); Univ. of Michigan, Ann Arbor, MI (United States). Atmospheric, Oceanic & Space Sciences (AOSS)
Publication Date:
Report Number(s):
Journal ID: ISSN 2169-9380
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 5; Journal ID: ISSN 2169-9380
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Space Science Inst., Boulder, CO (United States); Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); LANL Laboratory Directed Research and Development (LDRD) Program; National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; spacecraft charging; PIC simulations; contactor plasma; high-voltage electron beam; space beam experiments
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1402262