HARD X-RAY IMAGING OF INDIVIDUAL SPECTRAL COMPONENTS IN SOLAR FLARES

Journal Article · Sun Sep 20 04:00:00 EDT 2015 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/811/1/L1· OSTI ID:22518889

Caspi, Amir ^[1]; Shih, Albert Y. ^[2]; McTiernan, James M.; Krucker, Säm ^[3]

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1. Southwest Research Institute, Boulder, CO 80302 (United States)
2. Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
3. Space Sciences Laboratory University of California, Berkeley, CA 94720 (United States)

We present a new analytical technique, combining Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) high-resolution imaging and spectroscopic observations, to visualize solar flare emission as a function of spectral component (e.g., isothermal temperature) rather than energy. This computationally inexpensive technique is applicable to all spatially invariant spectral forms and is useful for visualizing spectroscopically determined individual sources and placing them in context, e.g., comparing multiple isothermal sources with nonthermal emission locations. For example, while extreme ultraviolet images can usually be closely identified with narrow temperature ranges, due to the emission being primarily from spectral lines of specific ion species, X-ray images are dominated by continuum emission and therefore have a broad temperature response, making it difficult to identify sources of specific temperatures regardless of the energy band of the image. We combine RHESSI calibrated X-ray visibilities with spatially integrated spectral models including multiple isothermal components to effectively isolate the individual thermal sources from the combined emission and image them separately. We apply this technique to the 2002 July 23 X4.8 event studied in prior works, and image for the first time the super-hot and cooler thermal sources independently. The super-hot source is farther from the footpoints and more elongated throughout the impulsive phase, consistent with an in situ heating mechanism for the super-hot plasma.

• OSTI ID: 22518889
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 811; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
DATA ANALYSIS
EXTREME ULTRAVIOLET RADIATION
GAMMA RADIATION
HARD X RADIATION
HEATING
HOT PLASMA
IMAGES
RESOLUTION
SOLAR FLARES
SUN