Laminar and Turbulent Plasmoid Ejection in a Laboratory Parker Spiral Current Sheet

Abstract

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-MHD code, NIMROD. This plasmoid formation is found to occur on a characteristic timescale 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, producing 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 2D models of solar streamers with a height of $3R_{\odot }$. This is consistent with the location and frequency at which periodic plasma blobs have been observed to form by LASCO and SECCHI instruments.

arXiv comment17 pages, 10 figures, 1 movie

References in corpus (13)

• Fast magnetic reconnection in the plasmoid-dominated regime
• A Model for the Sources of the Slow Solar Wind
• Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plasmas
• Origins of the Ambient Solar Wind: Implications for Space Weather
• Magnetic Reconnection Onset via Disruption of a Forming Current Sheet by the Tearing Instability
• Structure and Dynamics of the Sun's Open Magnetic Field
• Structured Slow Solar Wind Variability: Streamer-blob Flux Ropes and Torsional Alfvén Waves
• The Wisconsin Plasma Astrophysics Laboratory
• Anomalous Heating and Plasmoid Formation in a Driven Magnetic Reconnection Experiment
• In situ measurements of the variable slow solar wind near sector boundaries
• Charge States and FIP Bias of the Solar Wind from Coronal Holes, Active Regions, and Quiet Sun
• Weakly magnetized, Hall dominated plasma Couette flow
• Plasmoid instability in the semi-collisional regime

Cited by in corpus (1)

• Flux ropes and dynamics of the heliospheric current sheet