How to stop resonances of Alfvénic waves in coronal loops?

Edris Tajfirouze

Hosted by Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK on March 2, 2023


The corona is known to be replete with Alfvénic waves. These highly incompressible transverse oscillations are potential candidates to heat the solar corona as well as accelerating the solar wind particles. A possible mechanism for effective dissipation of Alfvénic waves is turbulence, a process through which energy cascades down to smaller scales where it can be dissipated efficiently by resistivity or diffusivity. To date, two main populations of Alfvénic modes in the corona have been identified namely, decayless standing modes and propagating modes. A intriguing observational fact is that Active Region (AR) loops show standing Alfvénic oscillations, while Quiet Sun (QS) loops show only propagating Alfvénic waves. We go beyond previous studies of MHD wave turbulence in coronal loops by using a realistic model atmosphere into and Reduced MHD model. We demonstrate that when the non-linear time-scale is greater than the Alfvén crossing time then it restricts the ability of loops to form a resonant cavity. Such a result could indicate that the waves observed in the QS loops are subject to a strong Alfvénic turbulence.

Co-authors: Richard Morton, Mahboubeh Asgari-Targhi

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