scholarly journals Coronal behavior before the large flare onset

2014 ◽  
Vol 66 (SP1) ◽  
pp. S17 ◽  
Author(s):  
Shinsuke Imada ◽  
Yumi Bamba ◽  
Kanya Kusano
Keyword(s):  
Large Flare

scholarly journals Stellar Flares: Observations and Theory

1989 ◽  
Vol 104 (2) ◽  
pp. 49-52
Author(s):  
Suzanne L. Hawley
Keyword(s):  
Scaling Law ◽  
Dynamic Scaling ◽  
X Ray ◽  
Temperature Distributions ◽  
Photometric And Spectroscopic Observations ◽  
Stellar Flares ◽  
Consistent Model ◽  
Self Consistent ◽  
Flare Model ◽  
Large Flare

AbstractPhotometric and spectroscopic observations of a very large flare on AD Leo are presented. A self consistent model of a flare corona, transition region and chromosphere is developed; in particular the chromospheric temperature distributions resulting from X-ray and EUV irradiation by coronae of various temperatures are determined. The predicted line fluxes in Hγ are compared to the observed line fluxes to find the coronal temperature as a function of time during the flare. This run of temperature with time is then compared with the predictions of an independent theoretical flare model based on a dynamic scaling law (see paper by Fisher and Hawley, these proceedings).

Understanding Space Weather: Part II: The Violent Sun

2017 ◽  
Vol 98 (11) ◽  
pp. 2387-2396 ◽  
Author(s):  
Keith T. Strong ◽  
Joan T. Schmelz ◽  
Julia L. R. Saba ◽  
Therese A. Kucera
Keyword(s):  
Solar System ◽  
Interplanetary Space ◽  
Navigation Systems ◽  
The Sun ◽  
Short Term ◽  
Radio Emissions ◽  
Electrical Grids ◽  
Large Flare ◽  
Major Eruption ◽  
Violent Events

Abstract The Sun is often racked by short-term violent events such as flares and coronal mass ejections (CMEs) but these two phenomena are often confused. Both are caused by the release of energy due to the reconnection of stressed and unstable magnetic fields. Flares bathe the solar system in electromagnetic radiation from gamma rays to radio emissions. CMEs throw billions of tons of solar plasma into interplanetary space at velocities of over 1,000 km s−1. Flares can occur without significant ejecta being spewed out from the Sun into the solar system. CMEs can occur without a significant flare being detected. The most violent and dangerous events occur when a large flare is accompanied by a major eruption. These violent events are much more common near solar maximum but can occur at any time during the solar cycle, so we are rarely completely immune to their effects. Various types of solar activity can lead to problems with electrical grids, navigation systems, and communications, and can present a hazard to astronauts, as will be discussed in future papers in this series.

scholarly journals Study on Large Flare Stacks (Part 1)

1970 ◽  
Vol 13 (12) ◽  
pp. 955-958 ◽  
Author(s):  
Tooru Honda ◽  
Toshiaki Makihata ◽  
Masatoshi Yoguchi ◽  
Hiroharu Hori ◽  
Takuzen Ito
Keyword(s):  
Large Flare

scholarly journals High Energy Phenomena in the Sun

1981 ◽  
Vol 94 ◽  
pp. 367-372
Author(s):  
Claudio Chiuderi
Keyword(s):  
Solar Flares ◽  
Solar Surface ◽  
Solar Physics ◽  
Total Duration ◽  
Cosmic Ray ◽  
Total Surface Area ◽  
High Energy ◽  
Energy Scale ◽  
Image Position ◽  
Large Flare

High energy phenomena in the solar physics context, simply means solar flares. To be sure, the energies attained during flares are certainly not very impressive on a cosmic-ray scale. The most energetic particles belong the GeV range, the highest temperatures are of the order of 107 K, γ-ray emission is occasional and the total energy emitted remains below 1033 ergs for all the flares so far observed. Apart from an absolute energy scale, flares are also energetically irrelevant on a solar scale. In fact in a large flare a few units in 1032 ergs are emitted, with a total duration of about one hour and a total surface area involved of a few units in 10−4 of the solar surface. Recalling the values of the luminosity, L⊙ ≃ 4 × 1033 erg s−1 and the solar flux F⊙6.3 × 1010 erg cm−2s−1, we see that

Correlated Bursts at Distant Sources on the Sun

1969 ◽  
Vol 1 (5) ◽  
pp. 186-188 ◽  
Author(s):  
K. Kai
Keyword(s):  
Time Delay ◽  
High Resolution ◽  
Active Regions ◽  
Solar Observatory ◽  
The Sun ◽  
Quiet Period ◽  
Fast Electrons ◽  
Different Sources ◽  
Large Flare

Since the start of high-resolution observations with the radioheliograph at the Culgoora Solar Observatory it has been noted that some bursts which occur from separate active regions could be physically correlated. It was suggested that the time delay between the correlated bursts is of the order of seconds, and that fast electrons provide the trigger. Wild found that shortly before a large flare weak bursts, stronelv polarized in the same sense, appeared simultaneously in different sources after a quiet period and he discussed the phenomenon in the light of flare mechanisms.

Solar neutron emissivity during the large flare on 1982 June 3

1987 ◽  
Vol 318 ◽  
pp. 913 ◽  
Author(s):  
E. L. Chupp ◽  
H. Debrunner ◽  
E. Flueckiger ◽  
D. J. Forrest ◽  
F. Golliez ◽  
...  
Keyword(s):  
Solar Neutron ◽  
Large Flare

scholarly journals A Bright Spot and a Serendipitous Stellar Flare on the Contact-Binary VW Cep

1983 ◽  
Vol 71 ◽  
pp. 481-483
Author(s):  
K.E. Egge ◽  
B.R. Pettersen
Keyword(s):  
Orbital Period ◽  
Triple System ◽  
Bright Spot ◽  
Stellar Flare ◽  
Flare Event ◽  
Main Contributor ◽  
The Third ◽  
Contact Binary ◽  
Photoelectric Observations ◽  
Large Flare

Almost twenty years ago a large flare event was observed on the prototype contact binary W UMa by Kuhi (1964). Similar events have been reported on 44 i Boo (Eggen 1948) and U Peg (Huruhata 1952) . In this paper we present photoelectric observations at three wavelengths of a flare on VW Cep. This is the first event of this kind to be reported for this star. VW Cep is a triple system. The main contributor to the visual flux is the eclipsing binary, consisting of a Kl primary and a G6 secondary (Kopal 1978), classified to be in contact. The orbital period is 6h 41m. Seven per cent of the total flux in the visual filter is due to the third component, a late K type dwarf at a distance of 12 AU from the eclipsing system (Hershey 1975).

scholarly journals The Secrets of EUVE J2056-17.1

1996 ◽  
Vol 152 ◽  
pp. 475-479
Author(s):  
M. Mathioudakis ◽  
J.J. Drake ◽  
N. Craig ◽  
D. Kilkenny ◽  
J.G. Doyle ◽  
...  
Keyword(s):  
Optical Spectrum ◽  
Flare Activity ◽  
Late Type ◽  
Spallation Reactions ◽  
Deep Survey ◽  
Large Flare

EUVE J2056-17.1 is one of the brightest sources in the First EUVE Source Catalog with 0.24 counts s−1 in the Deep Survey Lexan/B band. We present optical and EUV results that show this source is one of the most active late-type dwarfs. EUVE observed a large flare with energy in excess of 1035 ergs in its Lexan/B band. The quiescent optical spectrum of the source reveals strong hydrogen Balmer and Ca II H and K emission. A strong Li I 6707 Å line is also present in the spectrum. We have estimated a Li abundance of log N(Li) = 2.5±0.4. The high Li abundance and the high flare activity favors an interpretation where the enhanced Li is sustained by spallation reactions.

Observations of a large flare in GX 1+4 with the Compton Gamma Ray Observatory

1995 ◽  
Vol 15 (5) ◽  
pp. 119-122 ◽  
Author(s):  
R. Staubert ◽  
M. Maisack ◽  
E. Kendziorra ◽  
T. Draxler ◽  
M.H. Finger ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Large Flare
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