Laboratory Study of Arched Plasma Eruptions in a Sheared Magnetic Field

Solar atmosphere is carpeted with arched magnetic structures that confine millions degree hot plasma and drive energetic eruptions. We present results from a laboratory plasma experiment on spatio-temporal evolution of an arched magnetized plasma (β ≈ 10^-3, Lundquist number ≈ 10⁴, plasma radius/ion gyroradius ≈ 20) in a sheared magnetic configuration. The arched plasma is produced using a hot-cathode lanthanum hexaboride (LaB₆) source and it evolves in an ambient magnetized plasma produced by another LaB₆ source [1]. The experiment is designed to model conditions relevant to the formation and destabilization of similar structures in the solar atmosphere. In this experiment, magnitude of a nearly horizontal overlying magnetic field was varied to study its role in producing a sheared magnetic configuration and destabilizing the arched plasma [2]. Under eruptive conditions, large-scale ejections appear resembling characteristics of solar jets produced from emerging magnetic flux in a large-scale coronal field [3]. Nature and evolution of eruptive structures were investigated in the experiment using three-dimensional measurements of relevant plasma parameters.

References:

(1) Tripathi and Gekelman, Phys. Rev. Lett. 105, 075005 (2010)

(2) Sklodowski, Tripathi, and Carter, J. Plasma Phys. 87(6), 905870616 (2021)

(3) Archontis et. al., J. Astrophys. 635 (2), 1299 (2005)