Hard X-Ray Imaging of Individual Spectral Components in Solar Flares

Abstract

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.

9 pages, 5 figures

References in corpus (3)

• RHESSI Line and Continuum Observations of Super-hot Flare Plasma
• New Observations of the Solar 0.5-5 keV Soft X-ray Spectrum
• Constraining Solar Flare Differential Emission Measures with EVE and RHESSI

Cited by in corpus (17)

• Global Energetics of Solar Flares: V. Energy Closure in Flares and Coronal Mass Ejections
• Electron Power-Law Spectra in Solar and Space Plasmas
• Broad Non-Gaussian Fe XXIV Line Profiles in the Impulsive Phase of the 2017 September 10 X8.3 class Flare Observed by Hinode/EIS
• Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations
• New Solar Irradiance Measurements from the Miniature X-Ray Solar Spectrometer CubeSat
• A Fast, Simple, Robust Algorithm for Coronal Temperature Reconstruction
• The existence of hot X-ray onsets in solar flares
• First Results for Solar Soft X-ray Irradiance Measurements from the Third Generation Miniature X-Ray Solar Spectrometer
• The Multi-Instrument (EVE-RHESSI) DEM for Solar Flares, and Implications for Non-Thermal Emission
• Study of Time Evolution of Thermal and Non-Thermal Emission from an M-Class Solar Flare
• On the signatures of flare-induced global waves in the Sun: GOLF and VIRGO observations
• Ramaty High Energy Solar Spectroscopic Imager (RHESSI)
• Dual Origins of Rapid Flare Ribbon Downflows in an X9-class Solar Flare
• Superhot (> 30 MK) flare observations with STIX: Joint spectral fitting
• Visibility Interpolation in Solar Hard X-ray Imaging: Application to RHESSI and STIX
• Spectral component imaging of solar X-ray flares
• Radio, X-ray, and EUV signatures of internal and external reconnection of an erupting flux rope