Prominence activation, optical flare, and post-flare loops on the RS Canum Venaticorum star SZ Piscium

2018 ◽  
Vol 482 (1) ◽  
pp. 988-998 ◽  
Author(s):  
Dongtao Cao ◽  
Shenghong Gu ◽  
Jian Ge ◽  
Tinggui Wang ◽  
Jilin Zhou ◽  
...  
Keyword(s):  
Flare Loops ◽  
Optical Flare

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Prominences and Solar Activity

1979 ◽  
Vol 44 ◽  
pp. 357-372
Author(s):  
Z. Švestka
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
List Type ◽  
Type Number ◽  
Flare Loops ◽  
Filament Activation

The following subjects were discussed:(1)Filament activation(2)Post-flare loops.(3)Surges and sprays.(4)Coronal transients.(5)Disk vs. limb observations.(6)Solar cycle variations of prominence occurrence.(7)Active prominences patrol service.Of all these items, (1) and (2) were discussed in most detail and we also pay most attention to them in this report. Items (3) and (4) did not bring anything new when compared with the earlier invited presentations given by RUST and ZIRIN and therefore, we omit them.

Ballooning Instability in Coronal Flare Loops

Solar Physics ◽  
2008 ◽  
Vol 253 (1-2) ◽  
pp. 161-172 ◽  
Author(s):  
Y. T. Tsap ◽  
Y. G. Kopylova ◽  
A. V. Stepanov ◽  
V. F. Melnikov ◽  
K. Shibasaki
Keyword(s):  
Ballooning Instability ◽  
Flare Loops

Post-flare loops of 26 June 1992

Solar Physics ◽  
1996 ◽  
Vol 165 (2) ◽  
pp. 303-328 ◽  
Author(s):  
B. Schmieder ◽  
P. Heinzel ◽  
L. Van Driel-Gesztelyi ◽  
J. R. Lemen
Keyword(s):  
Flare Loops

Post-Flare Loops in the Chromosphere and Corona

1997 ◽  
pp. 85-93 ◽  
Author(s):  
L. Driel-Gesztelyi ◽  
J. E. Wiik ◽  
B. Schmieder
Keyword(s):  
Flare Loops

scholarly journals Spectroscopic Signatures of a Flare Observed by SUMER Onboard SOHO

2001 ◽  
Vol 203 ◽  
pp. 264-266
Author(s):  
I. E. Dammasch ◽  
W. Curdt ◽  
B. Kliem ◽  
B. N. Dwivedi ◽  
K. Wilhelm
Keyword(s):  
Time Series ◽  
Spatial Relationship ◽  
Solar Limb ◽  
Dynamical Behaviour ◽  
X Rays ◽  
Flare Loops ◽  
Limb Flare ◽  
Raster Scans ◽  
Lower Height ◽  
Spectroscopic Signatures

We report on EUV observations of a solar limb flare obtained by the SUMER spectrometer. A time series was taken with fixed slit position and several spectral windows that covered a wide temperature range (104-107 K), preceded and followed by contextual raster scans in a He I line. During the time series, a C4.6 flare occurred in the region, also imaged in the EUV by SOHO/EIT and in soft X rays by YOHKOH/SXT. The temporal evolution seen in the SUMER spectra reveals a close spatial relationship and a correlated dynamical behaviour of the hot (T ≈ 107 K) and cool (T ≈ 104 K) material, which are difficult to reconcile with the notion (based on the Kopp-Pneuman flare model) that cool loops form at a lower height than the hot flare loops.

scholarly journals OBSERVATIONS OF RECONNECTING FLARE LOOPS WITH THE ATMOSPHERIC IMAGING ASSEMBLY

2011 ◽  
Vol 742 (2) ◽  
pp. 92 ◽  
Author(s):  
Harry P. Warren ◽  
Casey M. O’Brien ◽  
Neil R. Sheeley
Keyword(s):  
Flare Loops

scholarly journals X-Ray Flares and Outflows Driven by Magnetic Interaction Between a Protostar and its Surrounding Disk

1997 ◽  
Vol 163 ◽  
pp. 717-718
Author(s):  
Mitsuru Hayashi ◽  
Kazunari Shibata ◽  
Ryoji Matsumoto
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Plasma Temperature ◽  
Magnetic Interaction ◽  
Central Star ◽  
X Ray ◽  
Mhd Simulations ◽  
Flare Loops ◽  
Hot Plasma ◽  
Dipole Magnetic Field

AbstractHere we present a model of hard X-ray flares and hot plasma outflows (optical jets) observed in protostars. Assuming that the dipole magnetic field of a protostar threads the protostellar disk, we carried out 2.5-dimensional magnetohydrodynamic (MHD) simulations of the diskstar interaction. The closed magnetic loops connecting the central star and the disk are twisted by the rotation of the disk. In the presence of resistivity, magnetic reconnection takes place in the current sheet formed inside the expanding loops. Hot, outgoing plasmoid and post flare loops are formed as a result of the reconnection. Numerical results are consistent with the observed plasma temperature (107 – 108K), the length of the flaring loop (1011 – 1012cm), and the speed of optical jets (200 – 400 km s−1 ).

scholarly journals Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3

2019 ◽  
Vol 486 (2) ◽  
pp. 1781-1795 ◽  
Author(s):  
Bhoomika Rajput ◽  
C S Stalin ◽  
S Sahayanathan ◽  
Suvendu Rakshit ◽  
Amit Kumar Mandal
Keyword(s):  
Spectral Energy Distribution ◽  
Broad Band ◽  
Temporal Correlation ◽  
Lorentz Factor ◽  
Degree Of Polarization ◽  
Spectral Energy ◽  
Long Duration ◽  
Γ Ray ◽  
Optical Flux ◽  
Optical Flare

ABSTRACT Blazars show optical and γ-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical, ultraviolet, X-ray, and γ-ray energies, spanning about 9 yr from 2008 August to 2017 February. We have identified four time intervals (epochs), A, B, D, and E, when the source showed large-amplitude optical flares. In epochs A and B the optical and γ-ray flares are correlated, while in D and E corresponding flares in γ-rays are weak or absent. In epoch B the degree of optical polarization strongly correlates with changes in optical flux during a short-duration optical flare superimposed on one of long duration. In epoch E the optical flux and degree of polarization are anticorrelated during both the rising and declining phases of the optical flare. We carried out broad-band spectral energy distribution (SED) modelling of the source for the flaring epochs A,B, D, and E, and a quiescent epoch, C. Our SED modelling indicates that optical flares with absent or weak corresponding γ-ray flares in epochs D and E could arise from changes in a combination of parameters, such as the bulk Lorentz factor, magnetic field, and electron energy density, or be due to changes in the location of the γ-ray-emitting regions.

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