EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Turbulence driven by chromospheric evaporations in solar flares

Wenzhi Ruan1, Chun Xia2, and Rony Keppens1
Wenzhi Ruan et al.
  • 1KU Leuven, Centre for mathematical Plasma Astrophysics (CmPA), Department of Mathematics, Leuven, Belgium (
  • 2School of Physics and Astronomy, Yunnan University, Kunming 650050, People’s Republic of China

Chromospheric evaporations are frequently observed at the footpoints of flare loops in flare events. The evaporations flows driven by thermal conduction or fast electron deposition often have high speed of hundreds km/s. Since the speed of the observed evaporation flows is comparable to the local Alfven speed, it is reasonable to consider the triggering of Kelvin-Helmholtz instabilities. Here we revisit a scenario which stresses the importance of the Kelvin-Helmholtz instability (KHI) proposed by Fang et al. (2016). This scenario suggests that evaporations flows from two footpoints of a flare loop can meet each other at the looptop and produce turbulence there via KHI. The produced KHI turbulence can play important roles in particle accelerations and generation of strong looptop hard X-ray sources. We investigate whether evaporation flows can produce turbulence inside the flare loop with the help of numerical simulation. KHI turbulence is successfully produced in our simulation. The synthesized soft X-ray curve demonstrating a clear quasi-periodic pulsation (QPP) with period of 26 s. The QPP is caused by a locally trapped, fast standing wave that resonates in between KHI vortices.

How to cite: Ruan, W., Xia, C., and Keppens, R.: Turbulence driven by chromospheric evaporations in solar flares, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11065,, 2021.


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