4.3 Article

Laminar and turbulent plasmoid ejection in a laboratory Parker Spiral current sheet

期刊

JOURNAL OF PLASMA PHYSICS
卷 87, 期 4, 页码 -

出版社

CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0022377821000775

关键词

space plasma physics; plasma simulation; plasma dynamics

资金

  1. NASA Earth and Space Sciences - Heliophysics Division Fellowship [NNX14AO16H]
  2. National Science Foundation
  3. DOE [DE-SC0018266]
  4. NSF-DOE Partnership in Basic Plasma Science and Engineering [PHY-2010136]
  5. NASA [677879, NNX14AO16H] Funding Source: Federal RePORTER
  6. U.S. Department of Energy (DOE) [DE-SC0018266] Funding Source: U.S. Department of Energy (DOE)

向作者/读者索取更多资源

Quasi-periodic plasmoid formation at the tip of magnetic streamer structures is observed to depend on pressure gradients and magnetic curvature in experiments and simulations. The presence of plasmoids is influenced by the system drive, with turbulent ejection occurring at higher drive levels, and a critical pressure gradient prevents plasmoid formation below this threshold.
Quasi-periodic plasmoid formation at the tip of magnetic streamer structures is observed to occur in experiments on the Big Red Ball as well as in simulations of these experiments performed with the extended magnetohydrodynamics code, NIMROD. This plasmoid formation is found to occur on a characteristic time scale dependent on pressure gradients and magnetic curvature in both experiment and simulation. Single mode, or laminar, plasmoids exist when the pressure gradient is modest, but give way to turbulent plasmoid ejection when the system drive is higher, which produces plasmoids of many sizes. However, a critical pressure gradient is also observed, below which plasmoids are never formed. A simple heuristic model of this plasmoid formation process is presented and suggested to be a consequence of a dynamic loss of equilibrium in the high-beta region of the helmet streamer. This model is capable of explaining the periodicity of plasmoids observed in the experiment and simulations, and produces plasmoid periods of 90 minutes when applied to two-dimensional models of solar streamers with a height of 3R(circle dot). This is consistent with the location and frequency at which periodic plasma blobs have been observed to form by Large Angle and Spectrometric Coronograph and Sun Earth Connection Coronal and Heliospheric Investigation instruments.

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