Anomalous-plasmoid-ejection-induced secondary magnetic reconnection: modeling solar flares and coronal mass ejections by laser–plasma experiments

Quan Dong ,Jianqiang Zhu,Neng Hua,Bobin Jiang,Shaoen Jiang,Kuixi Huang,Yongkun Ding,Yongjian Tang,Huigang Wei,Jie Zhang,Ming Chen,Gang Zhao,Xun Liu,Shoujun Wang,Yutong Li,Jiayong Zhong,Dawei Yuan,X T He ,Zheng-Ming Sheng ,M Y Yu ,Zhongliang Qiao ,Keming Du ,Xiaona Lin

doi:10.1017/hpl.2013.2

Abstract

AbstractThe driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings. In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense, and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.

Highlights

Flares and coronal mass ejections (CMEs) are two energetic solar phenomena with static magnetic field energy in the solar atmosphere impulsively released as electromagnetic radiations and plasma thermal and kinetic energies through magnetic reconnection (MR), of which process flares and CMEs are generally accepted as different but strongly coupled manifestations[1,2,3,4,5]
Impulsive solar flares and CMEs can be simulated in a laboratory by using two mutually approaching laser–plasma bubbles, as validated by the remarkable similarity between the two systems in morphology
The theoretically predicted anomalous plasmoid from the primary MR current sheet is demonstrated, which is expected to act as the possible initiation of CMEs if scaling the laboratory plasmas to astronomic plasmas

Summary

Introduction

Flares and coronal mass ejections (CMEs) are two energetic solar phenomena with static magnetic field energy in the solar atmosphere impulsively released as electromagnetic radiations and plasma thermal and kinetic energies through magnetic reconnection (MR), of which process flares and CMEs are generally accepted as different but strongly coupled manifestations[1,2,3,4,5]. As to the origin of CMEs, Shibata is the first person who, by statistically examining the correlation among characteristics of 15 Masuda-type solar flares, arrived at the conclusion that CMEs are initially the plasmoids gestated from a mother current sheet (or the primary CS). Even predictions of the formation of plasmoid in the MR current layer by various kinds of numerical simulations still require further observational and direct experimental evidence in the laboratory[15,19,22,23]. The plasmoid is expected to mimic the CMEs, and its behavior of stretching the primarily reconnected magnetic field lines to produce a secondary MR current sheet and two bright ridges (enlightened magnetic loops) is found for the first time in a laboratory, which is expected to mimic solar flares

Experiments

Euler similarity and dissipation differences

Summary