Site, size, spatial stability, and energetics of an X-ray flare kernel

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156730· OSTI ID:6470028

Petrasso, R; Gerassimenko, M; Nolte, J

We use S-054 Skylab and Solrad 9 observations to investigate the site, size, spatial stability, and energetics of an X-ray kernel during a flare in McMath 12512 on 1973 September 1 at approx.2300 UT. The kernel brightness peaked twice and varied by more than a factor of 10 during the 30 minute observations of the flare. During this time period the location of the kernel remained invariant to 3'', indicating that the flare process can occur repeatedly at the same location without large alteration of the magnetic structure. The emergence of the kernel coincided with the reported H..cap alpha.. flare onset, suggesting an intimate coupling between the X-ray kernel and H..cap alpha.. event. The positional stability, small size, and large electron density of the kernel, and also the temporal coincidence of the X-ray and H..cap alpha.. events, suggest that the kernel was located near the chromosphere and not high in the corona.At the first kernel brightness peak, its size was < or approx. =2'' and it accounted for 40% of the total flare flux. At the second kernel brightness peak we derived an emission measure of approx.10/sup 47/ cm/sup -3/, a volume of < or approx. =3 x 10/sup 24/ cm/sup 3/, an electron density of > or approx. =2 x 10/sup 11/ cm/sup -3/, a temperature of approx.10/sup 7/ K, a radiative power of approx.2 x 10/sup 24/ ergs s/sup -1/, and a magnetic field of > or approx. =10/sup 2/ gauss. The kernel accounted for 10% of the total flare flux and required a minimum power input of approx.2 x 10/sup 24/ ergs s/sup -1/ during its second rise phase. The minimal input power density of approx.1 ergs s/sup -1/ cm/sup -3/ is the same as estimates for the largest flares.

• Research Organization: American Science and Engineering, Inc., Cambridge, Massachusetts
• OSTI ID: 6470028
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 227:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics &amp; Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DATA
DATA FORMS
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
EXPERIMENTAL DATA
FUNCTIONS
INFORMATION
IONIZING RADIATIONS
ISOLATED VALUES
MAGNETIC FIELDS
NUMERICAL DATA
PHOTOGRAPHY
PLASMA
RADIATIONS
RESPONSE FUNCTIONS
SOLAR ACTIVITY
SOLAR FLARES
SOLAR RADIATION
TELESCOPES
X RADIATION