scholarly journals High-temperature solar flare plasma behaviour from crystal spectrometer observations

2015 ◽  
Vol 11 (S320) ◽  
pp. 80-85
Author(s):  
Barbara Sylwester ◽  
Janusz Sylwester ◽  
Kenneth J.H. Phillips ◽  
Anna Kepa ◽  
Tomasz Mrozek
Keyword(s):  
Emission Measure ◽  
Active Regions ◽  
Temperature Structure ◽  
Crystal Spectrometer ◽  
Evolutionary Patterns ◽  
Bent Crystal ◽  
Long Duration ◽  
Class B ◽  
Time Changes ◽  
Spectral Intensities

AbstractWe present results of analysis of the spectra collected with Polish instrument RESIK flown on CORONAS-F satellite. RESIK was the bent crystal spectrometer, measuring spectra in the spectral range 3.3 - 6.1 Å with a high cadence during flares. The emission lines as well as the continuum observed by RESIK are formed in hotter (T > 3 MK) plasmas of active regions and flares. RESIK observed various types of flares: from X-ray class B and C up to strongest flares of X-class, for both, short and long duration events. The analysis of absolute and relative spectral intensities of the lines and continuum observed for 33 events allowed for determining the plasma elemental composition with subsequent detailed study of time changes of the temperature structure of the sources described in terms of the differential emission measure (DEM). As an example we present the typical DEM evolutionary patterns for the C1.9 flare (SOL2002-12-26T08:35) and discuss its thermodynamics.

scholarly journals Soft X-Ray Spectroscopy from the X-Ray Polychromator on the Newly Repaired Solar Maximum Mission

1984 ◽  
Vol 86 ◽  
pp. 9-11
Author(s):  
K.T. Strong ◽  
R.A. Stern ◽  
J.R. Lemen ◽  
K.J.H. Phillips
Keyword(s):  
Spectroscopic Data ◽  
Solar Maximum ◽  
Active Regions ◽  
Line Profiles ◽  
Crystal Spectrometer ◽  
Solar Maximum Mission ◽  
X Ray ◽  
Bent Crystal ◽  
Mission Satellite ◽  
Short Presentation

The X-Ray Polychromator (XRP) resumed operations on 24 April 1984 following the successful in-orbit repair of the Solar Maximum Mission Satellite. Since that time the two instruments that comprise the XRP, the Flat Crystal Spectrometer (FCS) and the Bent Crystal Spectrometer (BCS), have been used to obtain new spectroscopic data from active regions and flares. The FCS, in particular, has accumulated far more observations of soft X-ray line profiles than were obtained during SMM-I in 1980. For this short presentation, we have chosen two topics to illustrate the type of data that we have obtained since the repair.

scholarly journals Spatially Resolved X-Ray Spectra of Coronal Active Regions

1975 ◽  
Vol 68 ◽  
pp. 67-67
Author(s):  
R. C. Catura ◽  
L. W. Acton ◽  
E. G. Joki ◽  
C. G. Rapley ◽  
J. L. Culhane
Keyword(s):  
Diffraction Pattern ◽  
Proportional Counter ◽  
Active Regions ◽  
Solar Image ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Bent Crystal ◽  
Spatially Resolved ◽  
Position Sensitive ◽  
Multiple Spot

SummaryX-ray spectra from a number of coronal active regions were obtained during ATM support rocket flights carried out by the Lockheed group on June 11 and December 19, 1973. Multi-grid collimators were used to provide fields of view of 40″ diameter and 90″ diameter for a number of scanning crystal spectrometers and a bent crystal spectrometer which employed a position sensitive proportional counter to register the diffracted spectrum. A solar image was produced on film and on a TV camera on board the rocket with the aid of a 1 Å Hα filter. A small part of the X-ray collimator was used to generate a multiple spot diffraction pattern which was superimposed on the Hα image and the composite picture was transmitted to the ground. Pre-launch calibrations allowed the spot corresponding to the X-ray collimator axis to be identified and so the collimator pointing direction on the solar disc was controlled from the ground by means of commands sent to the rocket.

scholarly journals Abundances of Potassium, Argon, and Sulphur in Solar Flares

2004 ◽  
Vol 219 ◽  
pp. 176-180
Author(s):  
K. J. H. Phillips ◽  
J. Sylwester ◽  
B. Sylwester ◽  
E. Landi
Keyword(s):  
Ionization Potential ◽  
Continuous Spectrum ◽  
Solar Flares ◽  
Emission Measure ◽  
Differential Emission Measure ◽  
Crystal Spectrometer ◽  
Isothermal Model ◽  
X Ray ◽  
Long Duration ◽  
First Ionization Potential

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.

Time Variations of the Calcium Elemental Abundance in Flares from NOAA Active Regions 2562 and 2779

1988 ◽  
Vol 102 ◽  
pp. 189-193
Author(s):  
J. Sylwester ◽  
M.-C. Zolcinski-Couet ◽  
R.D. Bentley ◽  
J.R. Lemen
Keyword(s):  
Solar Maximum ◽  
Active Regions ◽  
Elemental Abundance ◽  
Crystal Spectrometer ◽  
Solar Maximum Mission ◽  
Bent Crystal ◽  
Time Variations ◽  
Abundance Variation ◽  
Future Work

AbstractAnalysis of flare spectra obtained with the Bent Crystal Spectrometer aboard the Solar Maximum Mission (SMM) satellite enables the determination of the fluxes in the resonance (w) line of Ca XIX and the near-by continuum. The line-to-continuum intensity ratio is a sensitive measure of the calcium elemental abundance (Aca) relative to hydrogen in the emitting plasma. In previous investigations we found the calcium abundance varies from flare to flare. In the present investigation we analyse the variations ofAcafor flares which occurred in two active regions well observed bySMM. We conclude that it is not possible to correlate the abundance variations with the time of the flare occurrence as suggested in an earlier paper for flares produced from a single active region. Further, we find no convincing correlation of abundance variation with any other flare characteristics. This negative result will stimulate future work on the physical interpretation of the calcium abundance variation.

The Interpretation of Solar Spectral Intensities

1988 ◽  
Vol 102 ◽  
pp. 329
Author(s):  
R.W.P. McWhirter
Keyword(s):  
Emission Measure ◽  
Physical Nature ◽  
Atomic Data ◽  
The Sun ◽  
Atomic Properties ◽  
Outer Atmosphere ◽  
Spectral Intensities ◽  
Thin Plasma ◽  
Number Of Authors

The intensity of a specrtal line from an optically thin plasma such as the outer atmosphere of the sun depends on both the atomic properties of the atomic ion responsible for the line and the physical nature of the plasma. In this paper we discuss the various ways in which the measured spectral intensities from the sun are used to discover something about the nature of the sun’s atmosphere. The technique has been referred to as the emission measure method. It has important limitations in terms of the accuracy of the specrtal data as well as the atomic data. We discuss some of these and suggest methods by which they may be assessed. The technique is illustrated by application to real observations from a number of authors.

scholarly journals Interpretation of the X-Ray Spectra of Solar Active Regions

1975 ◽  
Vol 68 ◽  
pp. 73-100 ◽  
Author(s):  
Arthur B. C. Walker
Keyword(s):  
Transition Region ◽  
Rate Constant ◽  
Active Regions ◽  
Temperature Structure ◽  
Spectroscopic Techniques ◽  
Density Structure ◽  
Coronal Temperature ◽  
X Ray ◽  
Euv Spectrum

This paper presents a review of recent analytical studies of the coronal X-ray spectrum below 25 Å. The techniques used to compute the theoretical coronal spectrum, and the currently available atomic rate constant data are reviewed first. Spectroscopic techniques which have been proposed for the determination of coronal temperature and density structure, and the results derived from their application to coronal spectra are also reviewed.A number of coronal models based on X-ray observations have been developed recently, and the coronal temperature structure and composition predicted by these models is discussed, and compared with models of the corona and transition region derived from studies of the solar EUV spectrum.

Elliptically Bent Crystal Spectrometer for Z-Pinch Plasma X-Ray

2009 ◽  
Vol 36 (1) ◽  
pp. 115-118
Author(s):  
王洪建 Wang Hongjian ◽  
肖沙里 Xiao Shali ◽  
施军 Shi Jun ◽  
黄显宾 Huang Xianbin ◽  
杨礼兵 Yang Libing ◽  
...  
Keyword(s):  
Crystal Spectrometer ◽  
X Ray ◽  
Pinch Plasma ◽  
Bent Crystal ◽  
Z Pinch

Some New Methods of Precision X-Ray Spectrometry

1972 ◽  
Vol 16 ◽  
pp. 251-259 ◽  
Author(s):  
K. Das Gupta ◽  
Herbert Welch ◽  
P.F. Gott ◽  
John F. Priest ◽  
Sunny Cheng ◽  
...  
Keyword(s):  
Focal Point ◽  
Spectral Lines ◽  
Background Intensity ◽  
List Type ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Bent Crystal ◽  
The Third ◽  
Light Gathering Power ◽  
In Series

AbstractThree novel methods of x-ray spectrometry have been developed in recent years at Texas Tech University. These are:1. Three crystal spectrometer2. Two curved crystal spectrometer3. Spherically bent crystal spectrometer.In this paper the new design features, and experimental results will be discussed to indicate the usefulness of the new instruments. The three crystal spectrometer is a modified two crystal instrument. A third crystal is used to analyze the output of the two crystal spectrometer. The first two crystals are operated as a standard two crystal spectrometer. The third crystal is swept through the spectrum transmitted by the first two crystals for each setting of the first two crystals. The peak intensity of the third crystal sweep corresponds to the energy setting of the two crystal spectrometer, and is the intensity used to plot the spectral lines. The two curved crystal spectrometer utilizes two transmission spectrographs with radii having a 2:1 ratio in series, the crystal with the smaller radius being set so that its focal point falls on the Rowland circle of the larger radius crystal, This instrument has a very low background intensity and is suitable for precision scattering and diffraetion work. The spherically bent crystal spectrometer makes use of high light gathering power and high orders of reflection to allow high resolution studies of weak spectral lines. It also has the advantage of ease of alignment and operation.

scholarly journals The Temperature Structure of NGC 7027

1989 ◽  
Vol 131 ◽  
pp. 176-176
Author(s):  
C. T. Daub ◽  
J. P. Basart
Keyword(s):  
Temperature Distribution ◽  
Electron Temperature ◽  
Angular Resolution ◽  
Hot Spot ◽  
Emission Measure ◽  
The Other ◽  
Radio Continuum ◽  
Line Of Sight ◽  
Temperature Structure ◽  
Ngc 7027

Radio maps of the free-free radio continuum flux (angular resolution ≅ 1.3 arcseconds) from NGC 7027 were made with the VLA operating at 20-cm, 6-cm, and 2-cm wavelengths which are near and straddle unit optical depth. Mean line-of-sight electron temperature and emission measure distributions were calculated by pairing the 2-cm and 6-cm maps, and the electron temperature distribution on the near side of the nebula was then obtained from the 20-cm map. The results suggest that the energy balance is complex in this planetary. For example, mean line-of-sight temperatures are higher than average in the direction of one of the bright lobes but not in the direction of the other. Especially noteworthy is an apparent “hot spot” on the near side of the nebula which has no apparent relation to either of the bright lobes, but it is approximately coincident with the brightest portion of the optical image.

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