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Title: QUASI-PERIODIC PULSATIONS DURING THE IMPULSIVE AND DECAY PHASES OF AN X-CLASS FLARE

Abstract

Quasi-periodic pulsations (QPPs) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 2013 October 28. We focus on the character of the fine structure pulsations evident in the soft X-ray (SXR) time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of ∼20 s is observed in all channels and a second timescale of ∼55 s is observed in the non-thermal emissions. SXR pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the non-thermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from ∼40 s up to ∼70 s. We interpret the bursty nature of the co-existing multi-wavelength QPPs during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistentmore » thermal decay phase QPPs are most likely connected with compressive magnetohydrodynamic processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.« less

Authors:
;  [1]; ; ; ;  [2]
  1. School of Physics, Trinity College Dublin, Dublin 2 (Ireland)
  2. Solar Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
Publication Date:
OSTI Identifier:
22654243
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 827; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; AMPLITUDES; COMPARATIVE EVALUATIONS; CORRELATIONS; DECAY; EMISSION; FINE STRUCTURE; GAMMA RADIATION; HARD X RADIATION; MAGNETOHYDRODYNAMICS; MICROWAVE RADIATION; OSCILLATIONS; PERIODICITY; PLASMA; PLASMA HEATING; PULSATIONS; SOFT X RADIATION; SOLAR FLARES; SUN

Citation Formats

Hayes, L. A., Gallagher, P. T., Dennis, B. R., Ireland, J., Inglis, A. R., and Ryan, D. F. QUASI-PERIODIC PULSATIONS DURING THE IMPULSIVE AND DECAY PHASES OF AN X-CLASS FLARE. United States: N. p., 2016. Web. doi:10.3847/2041-8205/827/2/L30.
Hayes, L. A., Gallagher, P. T., Dennis, B. R., Ireland, J., Inglis, A. R., & Ryan, D. F. QUASI-PERIODIC PULSATIONS DURING THE IMPULSIVE AND DECAY PHASES OF AN X-CLASS FLARE. United States. doi:10.3847/2041-8205/827/2/L30.
Hayes, L. A., Gallagher, P. T., Dennis, B. R., Ireland, J., Inglis, A. R., and Ryan, D. F. Sat . "QUASI-PERIODIC PULSATIONS DURING THE IMPULSIVE AND DECAY PHASES OF AN X-CLASS FLARE". United States. doi:10.3847/2041-8205/827/2/L30.
@article{osti_22654243,
title = {QUASI-PERIODIC PULSATIONS DURING THE IMPULSIVE AND DECAY PHASES OF AN X-CLASS FLARE},
author = {Hayes, L. A. and Gallagher, P. T. and Dennis, B. R. and Ireland, J. and Inglis, A. R. and Ryan, D. F.},
abstractNote = {Quasi-periodic pulsations (QPPs) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 2013 October 28. We focus on the character of the fine structure pulsations evident in the soft X-ray (SXR) time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of ∼20 s is observed in all channels and a second timescale of ∼55 s is observed in the non-thermal emissions. SXR pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the non-thermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from ∼40 s up to ∼70 s. We interpret the bursty nature of the co-existing multi-wavelength QPPs during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistent thermal decay phase QPPs are most likely connected with compressive magnetohydrodynamic processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.},
doi = {10.3847/2041-8205/827/2/L30},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 827,
place = {United States},
year = {Sat Aug 20 00:00:00 EDT 2016},
month = {Sat Aug 20 00:00:00 EDT 2016}
}