Hard X-Ray Imaging of Solar Flares

<p>With the launch and commissioning of Solar Orbiter, the Spectrometer/Telescope for Imaging X-rays (STIX) is the latest hard X-ray telescope to study solar flares over a large range of flare sizes. STIX uses hard X-ray imaging spectroscopy in the range from 4 to 150 keV to diagnose the hottest temperature of solar flare plasma and the related nonthermal accelerated electrons. The unique orbit away from the Earth-Sun line in combination with the opportunity of joint observations with other Solar Orbiter instruments, STIX will provide new inputs into understanding the magnetic energy release and particle acceleration in solar flares. Commissioning observations showed that STIX is working as designed and therefore we report on the first solar microflare observations recorded on June 2020, when the spacecraft was at 0.52 AU from the Sun. STIX&#8217;s measurements are compared with Earth-orbiting observatories, such as GOES and SDO/AIA, for which we investigate and interpret the different temporal evolution. The detected early peak of the STIX profiles relative to GOES is due either by nonthermal X-ray emission of accelerated particles interacting with the dense chromosphere or the higher sensitivity of STIX toward hotter plasma.</p>

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Observations from the Hinotori mission

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1991.0085 ◽

1991 ◽

Vol 336 (1643) ◽

pp. 339-347 ◽

Cited By ~ 1

Keyword(s):

Solar Flares ◽

Bragg Diffraction ◽

High Dispersion ◽

X Rays ◽

Crystal Spectrometer ◽

Quartz Crystals ◽

X Ray ◽

X Ray Imaging ◽

Imaging Telescope ◽

First Time

The satellite Hinotori was launched in 1981 by the Institute of Space and Astronautical Science of Japan. Two major experiments on board the Hinotori satellite were a hard X-ray imaging telescope with modulation collimators, and a high dispersion soft X-ray crystal spectrometer utilizing the Bragg diffraction of X-rays on quartz crystals. These two instruments have revealed for the first time that solar flares show varying characteristics depending on the environment of flaring regions, and that flares produce plasmas as hot as 3-4 x 10 7 K.

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A statistical analysis of the soft X-ray profiles of solar flares

International Astronomical Union Colloquium ◽

10.1017/s0252921100154065 ◽

1989 ◽

Vol 104 (2) ◽

pp. 161-164

Author(s):

G. Pearce ◽

R.A. Harrison

Keyword(s):

Statistical Analysis ◽

Solar Flare ◽

Solar Flares ◽

Intensity Profile ◽

Imaging Spectrometer ◽

X Ray ◽

X Ray Imaging ◽

Selection Of

We undertake a statistical analysis of the soft X-ray (3.5 – 5.5 keV) profiles of solar flares as observed with the Hard X-ray Imaging Spectrometer on the SMM. The durations, maximum intensities and intensity profiles of the flares are examined. The properties of the “typical” solar flare are discussed. The distributions of the measured parameters with respect to one another reveal some interesting results. In common with past studies, we conclude that there is no evidence to suggest that more than one type of event is being viewed, despite a desire evident in the literature to place events into distinct groups. We also conclude that commonly held views about the relatonships between flare duration and intensity, profile asymmetries and intensity etc.. are in error. For more details of the flare events, the selection of data and the method of analysis, the reader is referred to Pearce and Harrison (1988).

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