REFLECTION OF PROPAGATING SLOW MAGNETO-ACOUSTIC WAVES IN HOT CORONAL LOOPS: MULTI-INSTRUMENT OBSERVATIONS AND NUMERICAL MODELING

Journal Article · Sat Sep 10 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/828/2/72· OSTI ID:22667457

Mandal, Sudip; Banerjee, Dipankar; Pant, Vaibhav ^[1]; Yuan, Ding; Fang, Xia

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1. Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

Slow MHD waves are important tools for understanding coronal structures and dynamics. In this paper, we report a number of observations from the X-Ray Telescope (XRT) on board HINODE and Solar Dynamic Observatory /Atmospheric Imaging Assembly (AIA) of reflecting longitudinal waves in hot coronal loops. To our knowledge, this is the first report of this kind as seen from the XRT and simultaneously with the AIA. The wave appears after a micro-flare occurs at one of the footpoints. We estimate the density and temperature of the loop plasma by performing differential emission measure (DEM) analysis on the AIA image sequence. The estimated speed of propagation is comparable to or lower than the local sound speed, suggesting it to be a propagating slow wave. The intensity perturbation amplitude, in every case, falls very rapidly as the perturbation moves along the loop and eventually vanishes after one or more reflections. To check the consistency of such reflection signatures with the obtained loop parameters, we perform a 2.5D MHD simulation, which uses the parameters obtained from our observation as inputs, and perform forward modeling to synthesize AIA 94 Å images. Analyzing the synthesized images, we obtain the same properties of the observables as for the real observation. From the analysis we conclude that a footpoint heating can generate a slow wave which then reflects back and forth in the coronal loop before fading. Our analysis of the simulated data shows that the main agent for this damping is anisotropic thermal conduction.

• OSTI ID: 22667457
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 828; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
COMPUTERIZED SIMULATION
DENSITY
EMISSION SPECTRA
MAGNETIC FIELDS
MAGNETOACOUSTIC WAVES
MAGNETOHYDRODYNAMICS
OSCILLATIONS
PERTURBATION THEORY
PLASMA
REFLECTION
SOLAR CORONA
SOUND WAVES
TELESCOPES
THERMAL CONDUCTION
ULTRAVIOLET RADIATION
VELOCITY
WAVE PROPAGATION
X RADIATION