High-resolution X-ray spectra of solar flares. IX - Mass upflow in the long-duration flare of 1979 June 5

1989 ◽  
Vol 345 ◽  
pp. 1079 ◽  
Author(s):  
G. A. Doschek ◽  
U. Feldman ◽  
J. F. Seely ◽  
D. L. McKenzie
1985 ◽  
Vol 292 ◽  
pp. 309 ◽  
Author(s):  
R. W. Kreplin ◽  
G. A. Doschek ◽  
U. Feldman ◽  
N. R., Jr. Sheeley ◽  
J. F. Seely

1989 ◽  
Vol 104 (1) ◽  
pp. 289-298
Author(s):  
Giovanni Peres

AbstractThis paper discusses the hydrodynamic modeling of flaring plasma confined in magnetic loops and its objectives within the broader scope of flare physics. In particular, the Palermo-Harvard model is discussed along with its applications to the detailed fitting of X-ray light curves of solar flares and to the simulation of high-resolution Caxix spectra in the impulsive phase. These two approaches provide complementary constraints on the relevant features of solar flares. The extension to the stellar case, with the fitting of the light curve of an X-ray flare which occurred on Proxima Centauri, demonstrates the feasibility of using this kind of model for stars too. Although the stellar observations do not provide the wealth of details available for the Sun, and, therefore, constrain the model more loosely, there are strong motivations to pursue this line of research: the wider range of physical parameters in stellar flares and the possibility of studying further the solar-stellar connection.


1998 ◽  
Vol 21 (7) ◽  
pp. 1015-1018 ◽  
Author(s):  
S.E. Boggs ◽  
R.P. Lin ◽  
P.T. Feffer ◽  
S. Slassi-Sennou ◽  
S. McBride ◽  
...  

1992 ◽  
Vol 9 ◽  
pp. 657-658
Author(s):  
J.L. Linsky

Although coronae for stars other than the Sun have previously been detected only in the X-ray and radio portions of the spectrum, the HST and future spacecraft sensitive to ultraviolet (UV) and extreme ultraviolet (ETIV) light will have the spectral resolution to study the dynamics and spectroscopic diagnostics of hot coronal plasmas. In the UV region accessible to HST, forbidden lines of FeXII at 1242 and 1349Å, of FeXXI at 1354Å, and other species seen in solar flares, are predicted to be present in the spectra of active stars. Upcoming observations with the Goddard High Resolution Spectrograph (GHRS) by S. Maran will search for these lines in the dM2e star AU Mic and other stars.


1981 ◽  
Vol 244 ◽  
pp. L141 ◽  
Author(s):  
J. L. Culhane ◽  
C. G. Rapley ◽  
R. D. Bentley ◽  
A. H. Gabriel ◽  
K. J. Phillips ◽  
...  

2006 ◽  
Vol 38 (7) ◽  
pp. 1482-1489 ◽  
Author(s):  
G.A. Doschek
Keyword(s):  

1986 ◽  
Vol 7 ◽  
pp. 731-738
Author(s):  
Ester Antonucci

AbstractThe observations obtained with high resolution spectrometers flown in the past solar maximum, in the years 1979-1981, have shown that the soft x-ray plasma during the impulsive phase of solar flares is characterized by upflows. as well as by isotropic flows, at velocities of a few hundred km s-1. Isotropic flows can be directly related to the primary energy release process. While, upflows are an indication of chromospheric material heated to coronal temperatures and evaporating along the magnetic fluxtubes; they are therefore related to the development of the coronal soft x-ray source in the flare region.


2004 ◽  
Vol 219 ◽  
pp. 176-180
Author(s):  
K. J. H. Phillips ◽  
J. Sylwester ◽  
B. Sylwester ◽  
E. Landi

Observations of the 3.3—6.1 Â X-ray line and continuous spectrum during four long-duration flares with the RESIK crystal spectrometer on the Coronas-F spacecraft have been analyzed to get the absolute abundances of potassium, argon, and sulphur. A differential emission measure of the form DEM ∝ exp(—Te/T0) was found to give the most consistent results of three models including an isothermal model. We obtained K/H = (3.7 ± 1.0) x 10—7, a factor 3 times photospheric; Ar/H = (2.8 ± 0.2) x 10—6, slightly lower than photospheric; and S/H = (2.2±0.4) x 10—5, approximately equal to photospheric. These measurements are consistent with a pattern in which elements with low (< 10 eV) first ionization potential are enriched in the corona by a factor of about 3 and elements of high first ionization potential have abundances approximately equal to photospheric.


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