Silicon X-ray line emission from solar flares and active regions

Solar Physics ◽  
1978 ◽  
Vol 60 (1) ◽  
pp. 123-136 ◽  
Author(s):  
John H. Parkinson ◽  
R. S. Wolff ◽  
H. L. Kestenbaum ◽  
W. H.-M. Ku ◽  
J. R. Lemen ◽  
...  
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
Active Regions ◽  
X Ray

scholarly journals SolpeX: the soft X-ray flare polarimeter–spectrometer for the ISS

2014 ◽  
Vol 10 (S305) ◽  
pp. 114-120
Author(s):  
Janusz Sylwester ◽  
Stefan Płocieniak ◽  
Jarosław Bakała ◽  
Żaneta Szaforz ◽  
Marek Stȩślicki ◽  
...  
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
Impulsive Phase ◽  
Particle Beams ◽  
X Ray ◽  
Hot Plasma ◽  
Spectral Imager ◽  
Polarized Bremsstrahlung ◽  
Made In ◽  
Fast Rotating

AbstractWe present the innovative soft X-ray spectro-polarimeter, SolpeX. This instrument consists of three functionally independent blocks. They are to be included into the Russian instrument KORTES, to be mounted onboard the ISS. The three SolpeX units are: a simple pin-hole X-ray spectral imager, a polarimeter, and a fast-rotating drum multiple-flat-crystal Bragg spectrometer. Such a combination of measuring blocks will offer a new opportunity to reliably measure possible X-ray polarization and spectra of solar flares, in particular during the impulsive phase. Polarized Bremsstrahlung and line emission due to the presence of directed particle beams will be detected, and measurements of the velocities of evaporated hot plasma will be made. In this paper we discuss the details of the construction of the SolpeX units. The delivery of KORTES with SolpeX to the ISS is expected to happen in 2017/2018.

Characteristics of Sunquake Events Observed in Solar Cycle 24

2021 ◽  
Author(s):  
Alexander Kosovichev ◽  
Ivan Sharykin
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Active Regions ◽  
Impulsive Phase ◽  
High Energy ◽  
Lower Atmosphere ◽  
Solar Dynamics Observatory ◽  
X Ray ◽  
Solar Cycle 24 ◽  
Cycle 24

<p>Helioseismic response to solar flares ("sunquakes") occurs due to localized force or/and momentum impacts observed during the flare impulsive phase in the lower atmosphere. Such impacts may be caused by precipitation of high-energy particles, downward shocks, or magnetic Lorentz force. Understanding the mechanism of sunquakes is a key problem of the flare energy release and transport. Our statistical analysis of M-X class flares observed by the Solar Dynamics Observatory during Solar Cycle 24 has shown that contrary to expectations, many relatively weak M-class flares produced strong sunquakes, while for some powerful X-class flares, helioseismic waves were not observed or were weak. The analysis also revealed that there were active regions characterized by the most efficient generation of sunquakes during the solar cycle. We found that the sunquake power correlates with maximal values of the X-ray flux derivative better than with the X-ray class. The sunquake data challenge the current theories of solar flares.</p>

YOHKOH Observations of Fe XXVI X-Ray Line Emission from Solar Flares

1996 ◽  
Vol 464 ◽  
pp. 487 ◽  
Author(s):  
C. D. Pike ◽  
K. J. H. Phillips ◽  
J. Lang ◽  
A. Sterling ◽  
T. Watanabe ◽  
...  
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
X Ray

scholarly journals Major solar flares without coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 283-286 ◽  
Author(s):  
N. Gopalswamy ◽  
S. Akiyama ◽  
S. Yashiro
Keyword(s):  
Open Field ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Active Regions ◽  
High Energy ◽  
X Ray ◽  
Type Iii ◽  
High Energy Electrons ◽  
Field Lines ◽  
Microwave Bursts

AbstractWe examine the source properties of X-class soft X-ray flares that were not associated with coronal mass ejections (CMEs). All the flares were associated with intense microwave bursts implying the production of high energy electrons. However, most (85%) of the flares were not associated with metric type III bursts, even though open field lines existed in all but two of the active regions. The X-class flares seem to be truly confined because there was no material ejection (thermal or nonthermal) away from the flaring region into space.

scholarly journals Plasma Processes in Solar Flares

1990 ◽  
Vol 142 ◽  
pp. 355-364
Author(s):  
V.M. Tomozov
Keyword(s):  
Solar Flares ◽  
Large Scale ◽  
Stark Effect ◽  
Active Regions ◽  
Theoretical Models ◽  
Radio Bursts ◽  
X Ray ◽  
Plasma Effects ◽  
Collective Plasma

A rationale is presented for a conception that appearance of flares in active regions is due to the interaction of large-scale convective elements. Such an interaction gives rise to shear motions in the vicinity of the inverse polarity line of the photospheric magnetic field which generate vortical motions leading to non-equilibrium state of the magnetic configuration. Modern concepts of manifestations of turbulent plasma processes are described in terms of theoretical models for solar flares. Plasma effects arising at propagation of electron beams and thermal fluxes in the solar atmosphere are considered. Their role in the interpretation of hard X-ray and type III radio bursts is pointed out. The role of the turbulent Stark effect for diagnostics of collective plasma processes in solar flares is emphasized.

scholarly journals X-ray Line Formation in Astrophysical Environments: The L-shell Spectra of Ionized Iron

1990 ◽  
Vol 115 ◽  
pp. 49-52
Author(s):  
Duane A. Liedahl ◽  
Steven M. Kahn ◽  
Albert L. Osterheld ◽  
William H. Goldstein
Keyword(s):  
Excited States ◽  
Energy Levels ◽  
Line Emission ◽  
Active Regions ◽  
Dielectronic Recombination ◽  
Resonance Excitation ◽  
Astrophysical Plasmas ◽  
X Ray ◽  
Wide Range ◽  
Atomic Energy Levels

AbstractWe have initiated an extensive atomic modeling effort applicable to X-ray line emission in high-temperature astrophysical plasmas. The emphasis of our program is on the detailed accounting of the mechanisms which populate excited states of highly ionized atoms over a wide range of electron temperatures and densities. As a first demonstration we have calculated spectra for the important L -shell ions Fe XVI-XIX in a complete collisional-radiative model under conditions appropriate to solar coronal plasmas. Using methods presented here, we have synthesized the X-ray spectra of solar flares and active regions over the wavelength interval 13 – 18 Ǡ. The atomic model, which includes 705 atomic energy levels, is the largest and most detailed of its kind. In this introductory paper, we discuss the effects of dielectronic recombination on the spectrum of Fe XVII and present a new technique whereby the 3s lines can be used as a diagnostic of the electron temperature. Also included are new values for the rate of resonance excitation of the n=3 Fe XVII excited states. These rates are lower than those previously obtained and suggest that resonance excitation does not contribute significantly to the population kinetics. Finally, we present a direct comparison of our a calculated model spectrum with data from a solar flare.

The relation between hard X-ray and transition-region line emission in solar flares

Solar Physics ◽  
1985 ◽  
Vol 96 (2) ◽  
pp. 317-330 ◽  
Author(s):  
John T. Mariska ◽  
A. I. Poland
Keyword(s):  
Transition Region ◽  
Solar Flares ◽  
Line Emission ◽  
X Ray ◽  
Region Line

scholarly journals Spectroscopic Diagnostics for Ions Observed in Solar and Cosmic Plasmas

1990 ◽  
Vol 115 ◽  
pp. 11-20 ◽  
Author(s):  
Helen E Mason
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
Wavelength Region ◽  
Spectral Lines ◽  
Emission Lines ◽  
Atomic Processes ◽  
X Ray ◽  
Spectroscopic Diagnostics ◽  
Solar Spectral Line ◽  
Diagnostic Properties

AbstractThe X-ray wavelength region (1-200Å) is rich in spectral lines from highly ionised systems. Spectra from the solar atmosphere have been studied extensively with various instruments covering different wavelength regions. In this paper, we discuss the solar spectral line emission with particular reference to iron ions and helium like ions observed during solar flares. The atomic processes involved in the calculation of theoretical intensities for low density plasmas are outlined together with the diagnostic properties of the emission lines. Comparisons are made with available cosmic X-ray spectra and predicted spectra for future projects, such as AXAF.

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