Frustrated relaxation and instabilities in coronal heating and solar wind formation
Abstract
Coronal heating modeling includes the spontaneous formation of quasi-singular current sheets from the smooth photospheric driving. In this presentation we discuss the difference between the corona as describable by "smooth" force-free extrapolations and a corona that is in a state not of passive relaxation but of what we call a state of "frustrated relaxation": a state where relaxation is incomplete and condemned to continuous local dynamics - and coronal heating - due to photospheric forcing. Such a state is continuously forced and slowly marching to the catastrophic instability or loss of equilibrium of CMEs. Our presentation explores frustrated relaxation in the corona via modeling, numerical simulations and observations. We will in particular describe the process of current sheet formation as one due to a state of magnetically dominated turbulence. But we will also describe the loss of coronal confinement caused by Rayleigh-Taylor and ballooning -like instability in the heated plasma around complex magnetic field topologies, a solar wind source that has been almost neglected in the past. We will specifically demonstate that current sheet formation is a nonlinear process that is not simply describable in terms of discontinuities, and also provide a path for turbulence modeling of the corona and accelerating solar wind.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.1502V