POTENTIAL evidence for the onset of alfvénic turbulence in trans-equatorial coronal loops

I. De Moortel, S. W. McIntosh, J. Threlfall, C. Bethge, J. Liu

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18 Citations (Scopus)

Abstract

This study investigates Coronal Multi-channel Polarimeter Doppler-shift observations of a large, off-limb, trans-equatorial loop system observed on 2012 April 10-11. Doppler-shift oscillations with a broad range of frequencies are found to propagate along the loop with a speed of about 500 km s-1. The power spectrum of perturbations travelling up from both loop footpoints is remarkably symmetric, probably due to the almost perfect north-south alignment of the loop system. Compared to the power spectrum at the footpoints of the loop, the Fourier power at the apex appears to be higher in the high-frequency part of the spectrum than expected from theoretical models. We suggest this excess high-frequency power could be tentative evidence for the onset of a cascade of the low-to-mid frequency waves into (Alfvénic) turbulence.

Original languageEnglish
Article numberL34
Number of pages6
JournalAstrophysical Journal Letters
Volume782
Issue number2
Early online date20 Feb 2014
DOIs
Publication statusPublished - 20 Feb 2014
Externally publishedYes

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