English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report decaying quasi-periodic intensity oscillations in the X-ray (6-12keV) and extreme ultraviolet (EUV) channels (131, 94, 1600, 304 \AA) observedby the Fermi GBM (Gamma-ray Burst Monitor) and SDO/AIA, respectively, during aC-class flare. The estimated period of oscillation and decay time in the X-raychannel (6-12 keV) was about 202 s and 154 s, respectively. A similaroscillation period was detected at the footpoint of the arcade loops in the AIA1600 and 304 \AA channels. Simultaneously, AIA hot channels (94 and 131 \AA)reveal propagating EUV disturbances bouncing back and forth between thefootpoints of the arcade loops. The period of the oscillation and decay timewere about 409 s and 1121 s, respectively. The characteristic phase speed ofthe wave is about 560 km/s for about 115 Mm loop length, which is roughlyconsistent with the sound speed at the temperature about 10-16 MK (480-608km/s). These EUV oscillations are consistent with the SOHO/SUMER Doppler-shiftoscillations interpreted as the global standing slow magnetoacoustic waveexcited by a flare. The flare occurred at one of the footpoints of the arcadeloops, where the magnetic topology was a 3D fan-spine with a null-point.Repetitive reconnection at this footpoint could cause the periodic accelerationof non-thermal electrons that propagated to the opposite footpoint along thearcade and precipitating there, causing the observed 202-s periodicity. Otherpossible interpretations, e.g. the second harmonics of the slow mode are alsodiscussed.

X-ray and EUV Observations of Simultaneous Short and Long Period Oscillations in Hot Coronal Arcade Loops