Quasi-periodic pulsations with varying period in multi-wavelength observations of an X-class flare

Journal Article · Sun Aug 10 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/791/1/44· OSTI ID:22365391

Huang, Jing; Tan, Baolin; Zhang, Yin ^[1]; Karlický, Marian; Mészárosová, Hana ^[2]

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1. Key Laboratory of Solar Activities, National Astronomical Observatories Chinese Academy of Sciences, Beijing 100012 (China)
2. Astronomical Institute of the Academy of Sciences of the Czech Republic, CZ-25165 Ondřejov (Czech Republic)

This work presents an interesting phenomenon of the period variation in quasi-periodic pulsations (QPPs) observed during the impulsive phase of a coronal mass ejection-related X1.1 class flare on 2012 July 6. The period of QPPs was changed from 21 s at soft X-rays (SXR) to 22-23 s at microwaves, to ∼24 s at extreme ultraviolet emissions (EUV), and to 27-32 s at metric-decimetric waves. The microwave, EUV, and SXR QPPs, emitted from flare loops of different heights, were oscillating in phase. Fast kink mode oscillations were proposed to be the modulation mechanism, which may exist in a wide region in the solar atmosphere from the chromosphere to the upper corona or even to the interplanetary space. Changed parameters of flare loops through the solar atmosphere could result in the varying period of QPPs at different wavelengths. The first appearing microwave QPPs and quasi-periodic metric-decimetric type III bursts were generated by energetic electrons. This may imply that particle acceleration or magnetic reconnection were located between these two non-thermal emission sources. Thermal QPPs (in SXR and EUV emissions) occurred later than the nonthermal ones, which would suggest a some time for plasma heating or energy dissipation in flare loops during burst processes. At the beginning of flare, a sudden collapse and expansion of two separated flare loop structures occurred simultaneously with the multi-wavelength QPPs. An implosion in the corona, including both collapse and expansion of flare loops, could be a trigger of loop oscillations in a very large region in the solar atmosphere.

• OSTI ID: 22365391
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 791; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
CHROMOSPHERE
EMISSION
ENERGY LOSSES
EXPANSION
EXTREME ULTRAVIOLET RADIATION
INTERPLANETARY SPACE
MAGNETIC RECONNECTION
MASS
MICROWAVE RADIATION
MODULATION
OSCILLATION MODES
OSCILLATIONS
PERIODICITY
PLASMA HEATING
PULSATIONS
SOFT X RADIATION
SUN
WAVELENGTHS