Simulations of solar filament fine structures and their counterstreaming flows

Abstract

Solar filaments, also called solar prominences when appearing above the solar limb, are cold, dense materials suspended in the hot tenuous solar corona, consisting of numerous long, fibril-like threads. These threads are the key to disclosing the physics of solar filaments. Similar structures also exist in galaxy clusters. Besides their mysterious formation, filament threads are observed to move with alternating directions, which are called counterstreaming flows. However, the origin of these flows has not been clarified yet. Here we report that turbulent heating at the solar surface is the key, which randomly evaporates materials from the solar surface to the corona, naturally reproducing the formation and counterstreamings of the sparse threads in the solar corona. We further suggest that while the cold Hα counterstreamings are mainly due to longitudinal oscillations of the filament threads, there are million-kelvin counterstreamings in the corona between threads, which are alternating unidirectional flows.

Persistent fast kink magnetohydrodynamic waves detected in a quiescent prominence

“…As one of the most surprising structures suspended by coronal magnetic fields, solar prominences are often *Corresponding authors (Dong Li, email: lidong@pmo.ac.cn; Ding Yuan, email: yuanding@hit.edu.cn) regarded as the source/driver of solar eruptions, especially for the large-scale eruption, such as the solar flare or coronal mass ejection [3,4]. High-resolution observations suggest that they typically consist of a large number of dynamic thread-like structures [5][6][7][8][9][10], and such thread-like structures also exist in the galaxy clusters [11]. These dynamic behaviors are often linked to the magnetic activities in the corona [12][13][14][15][16], and are therefore employed to understand the origin and physical properties of solar prominences.…”

When hot meets cold: post-flare coronal rain

“…Indeed, the temperature of bright loops in this 17.1 passband (about 10 5.8 K) is not far from the critical temperature for the onset of catastrophic cooling (this is density and temperature dependent, but generally happens below 2 MK according to [41]). Condensations can be triggered by thermal instability near bright loops and these suddenly formed structures grow fastest across magnetic field lines (counterintuitive due to the field-aligned thermal conduction, but see [22,29,30,42]).…”

Editorial: Data-Driven MHD - Novel Applications to the Solar Atmosphere

“…1) The complex plasma dynamics and energetics of the solar atmosphere are governed by the combined interplay of the plasma and magnetic fields. The current trends of the understanding of Sun's magnetic field origin and its data driven modelling are at the fore-front of the solar research, and there are extensive attempts made in recent days on this very important scientific theme (Bobra et al, 2008;Cheung and DeRosa, 2012;Kliem et al, 2013;Dalmasse et al, 2019;Zhou et al, 2020;Yardley et al, 2021). The paper titled "MHD Modelling of Solar Coronal Magnetic Evolution Driven by Photospheric Flow" by Jiang et al depicted a cutting edge perspective of the data-driven MHD simulations of magnetic fields generated in the solar active region (AR).…”