Diagnostics of Flaring Loop Parameters

Huang, Guangli; Melnikov, V. F.; Ji, Haisheng; Ning, Zhouyu

doi:10.1007/978-981-10-2869-4_6

Cited by 1 publication

(1 citation statement)

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“…The EM was measured to be 3.7 ±1.8 • 10 27 cm −5 , and the temperature 1.5 ±0.5 • 10 6 K. If we assume that the column depth was about 3-5 pixels, namely h = 1.8 ±0.6 • 10 6 m, then the number density of electrons was estimated with n e = EM/0.83h = 5.0 ±1.5 • 10 10 cm −3 (also see Aschwanden et al 2013). This blob of material had a plasma density at the level of flaring loops (Huang et al 2018).…”

Section: Heating Effectmentioning

confidence: 99%

Multilayered Kelvin–Helmholtz Instability in the Solar Corona

Yuan

Shen

Liu

et al. 2019

ApJL

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The Kelvin-Helmholtz (KH) instability is commonly found in many astrophysical, laboratory, and space plasmas. It could mix plasma components of different properties and convert dynamic fluid energy from large scale structure to smaller ones. In this study, we combined the ground-based New Vacuum Solar Telescope (NVST) and the Solar Dynamic Observatories (SDO) / Atmospheric Imaging Assembly (AIA) to observe the plasma dynamics associated with active region 12673 on 09 September 2017. In this multi-temperature view, we identified three adjacent layers of plasma flowing at different speeds, and detected KH instabilities at their interfaces. We could unambiguously track a typical KH vortex and measure its motion. We found that the speed of this vortex suddenly tripled at a certain stage. This acceleration was synchronized with the enhancements in emission measure and average intensity of the 193Å data. We interpret this as evidence that KH instability triggers plasma heating. The intriguing feature in this event is that the KH instability observed in the NVST channel was nearly complementary to that in the AIA 193Å. Such a multi-thermal energy exchange process is easily overlooked in previous studies, as the cold plasma component is usually not visible in the extreme ultraviolet channels that are only sensitive to high temperature plasma emissions. Our finding indicates that embedded cold layers could interact with hot plasma as invisible matters. We speculate that this process could occur at a variety of length scales and could contribute to plasma heating.

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Section: Heating Effectmentioning

confidence: 99%