Direct Spatial Association of an X-Ray Flare with the Eruption of a Solar Quiescent Filament Gordon D. Holman and Adi Foord （２０１５） Solar Seminar on July 13, 2015 Kumi Hirose

1.Introduction  Understanding of the conditions that affect the origin, magnitude end evolution of the solar flare ↓ Understanding and predicting flare and space weather  Most flares occur in active regions. However, flares are occasionally observed in Hα from spotless region of the Sun. ↑ In most cases, these flares are associated with the eruption of a quiescent filament. Quiescent filamentsActive region filaments sizelongershorter magnetic fieldweakerstronger

GOES and RHESSI  Solar flares are identified through their enhancement of the soft X-ray emission detected by GOES, which continuously observe the spatially integrated X-ray flux from the Sun in soft X-ray band (1-8 Å ) and hard X-ray band (0.5-4 Å ).  The combination of this two bands of GOES provides a measure of the temperature and emission measure of the emitting plasma.  RHESSI provides spectroscopic imaging of solar flares from soft X-rays to γ-rays, from 3keV(4 Å ) to 17Mev photon energies.  RHESSI observations of flare and microflares have indicated that the X-ray flare only occur in active regions.

In this paper…  Report on a quiescent filament eruption with associated GOES and RHESSI X-ray emission  The eruption is observed in EUV images from SDO/AIA.  The RHESSI X-ray emission to be spatially compact, but directly associated with the quiescent filament eruption. (It is not located in an active region or associated with an active region flare.)

2.Data Analysis

Movie of the filament eruption  9/SDO_ _304_4k.webmhd.webm 9/SDO_ _304_4k.webmhd.webm

GOES → RHESSI → Fermi → Light curves

The peak of the RHESSI emission moved westward with the western ribbon.

Magnetogram with superimposed RHESSI image contours and dipole (emerging flux region)

A barb is seen extending downward toward the small dipole before the filament eruption. The presence of the barb provides evidence for a magnetic connection between the small dipole and the magnetic structure supporting the filament.

The evolution of the small dipole before the filament eruption

3.Conclusions The X-ray flare can be directly associated with the eruption of a quiescent filament and can occur outside an active region. The X-ray flare clearly does not cause the filament eruption. The presence of a small but intense dipolar magnetic region below the filament. The X-ray flare is only seen near the location of the dipolar region.

Summary  This study is about the eruption of the quiescent filament began at about 21:00 UT on 2013 September 29.  The X-ray flare can be directly associated with the eruption of a quiescent filament and can occur outside an active region.  Magnetic field strengths are provided by a small dipolar structure located beneath the filament and adjacent to the location of the X-ray emission.  The emerging flux region contributed to the triggering of the filament eruption.