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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Quasi-periodic pulsations (QPP) are often observed in X-ray emission fromsolar flares. To date, it is unclear what their physical origins are. Here, wepresent a multi-instrument investigation of the nature of QPP during theimpulsive and decay phases of the X1.0 flare of 28 October 2013. We focus onthe character of the fine structure pulsations evident in the soft X-ray timederivatives and compare this variability with structure across multiplewavelengths including hard X-ray and microwave emission. We find that duringthe impulsive phase of the flare, high correlations between pulsations in thethermal and non-thermal emissions are seen. A characteristic timescale of ~20sis observed in all channels and a second timescale of ~55s is observed in thenon-thermal emissions. Soft X-ray pulsations are seen to persist into the decayphase of this flare, up to 20 minutes after the non-thermal emission hasceased. We find that these decay phase thermal pulsations have very smallamplitude and show an increase in characteristic timescale from ~40s up to~70s. We interpret the bursty nature of the co-existing multi-wavelength QPPduring the impulsive phase in terms of episodic particle acceleration andplasma heating. The persistent thermal decay phase QPP are most likelyconnected with compressive MHD processes in the post-flare loops such as thefast sausage mode or the vertical kink mode.

Quasi-Periodic Pulsations during the Impulsive and Decay phases of an X-class Flare