scholarly journals Unique Properties of Thermally Tailored Copper: Magnetically Active Regions and Anomalous X-ray Fluorescence Emissions

2009 ◽  
Vol 113 (51) ◽  
pp. 21428-21440
Author(s):  
Christopher J. Nagel ◽  
Dudley R. Herschbach
Keyword(s):  
Active Regions ◽  
X Ray

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.

scholarly journals X-Ray Spectra of Solar Active Regions

1975 ◽  
Vol 68 ◽  
pp. 45-64 ◽  
Author(s):  
John H. Parkinson
Keyword(s):  
Spectral Resolution ◽  
Active Regions ◽  
X Ray ◽  
Quantitative Theory ◽  
Great Progress ◽  
Solar Active Regions ◽  
Cascading Processes ◽  
Weak Satellite

The last few years have seen great progress in our understanding of X-ray spectra of solar active regions. This paper demonstrates both the usefulness and the limitations of the techniques, both scientific and instrumental, that have recently become available. Improvements in spectral resolution led to the discovery of weak satellite lines to helium-like ions; the quantitative theory for these lines is also discussed. The observed intensities of the Fe XVII lines are also investigated and found to be in agreement with calculations that allow for cascading processes.

scholarly journals Statistical Properties of Magnetic Separators in Model Active Regions

2000 ◽  
Vol 195 ◽  
pp. 443-444
Author(s):  
B. T. Welsch ◽  
D. W. Longcope
Keyword(s):  
Active Region ◽  
Solar Corona ◽  
Magnetic Reconnection ◽  
First Principles ◽  
Magnetic Charge ◽  
Active Regions ◽  
Heating Rates ◽  
X Ray ◽  
Field Lines ◽  
Charge Topology

“Transient brightenings” (or “microflares”) regularly deposit 1027 ergs of energy in the solar corona, and account for perhaps 20% of the active corona's power (Shimizu 1995). We assume these events correspond to episodes of magnetic reconnection along magnetic separators in the solar corona. Using the techniques of magnetic charge topology, we model active region fields as arising from normally distributed collections of “magnetic charges”, point-like sources/sinks of flux (or field lines). Here, we present statistically determined separator (X-ray loop) lengths, derived from first principles. We are in the process of statistical calculations of heating rates due to reconnection events along many separators.

X-Ray and microwave observations of active regions

Solar Physics ◽  
1983 ◽  
Vol 85 (2) ◽  
pp. 267-283 ◽  
Author(s):  
D. F. Webb ◽  
J. M. Davis ◽  
M. R. Kundu ◽  
T. Velusamy
Keyword(s):  
Active Regions ◽  
X Ray

Normal Incidence X-Ray Telescope Power Spectra of X-Ray Emission from Solar Active Regions. II. Theory

1993 ◽  
Vol 405 ◽  
pp. 773 ◽  
Author(s):  
Daniel O. Gomez ◽  
Petrus C. H. Martens ◽  
Leon Golub
Keyword(s):  
Power Spectra ◽  
Active Regions ◽  
Normal Incidence ◽  
X Ray ◽  
Solar Active Regions

A Discussion on the physics of the solar atmosphere - Spectroscopic studies of the solar corona at x-ray wavelengths

1976 ◽  
Vol 281 (1304) ◽  
pp. 383-390 ◽  
Keyword(s):  
Spatial Distribution ◽  
Solar Corona ◽  
Spatial Variation ◽  
Resonance Line ◽  
Active Regions ◽  
Resonance Scattering ◽  
Spectroscopic Studies ◽  
Line Of Sight ◽  
X Ray ◽  
Forbidden Transitions

The spatial distribution of the emission in several X-ray lines is discussed with emphasis on temperature dependence and association with active regions. New results are presented for the trio of helium-like O vii lines which demonstrate (1) a spatial variation in the density dependent forbidden to intersystem line ratio, and (2) a strong spatial variation in the intensity of the O vii resonance line relative to the optically forbidden transitions. The second effect appears to be caused by resonance scattering by material in the line of sight.

scholarly journals Dynamic Events in the X-Ray Corona (A Progress Report from the AS&E X-ray Telescope on Skylab)

1974 ◽  
Vol 57 ◽  
pp. 501-504 ◽  
Author(s):  
G. S. Vaiana ◽  
A. S. Krieger ◽  
J. K. Silk ◽  
A. F. Timothy ◽  
R. C. Chase ◽  
...  
Keyword(s):  
Active Region ◽  
Large Scale ◽  
Active Regions ◽  
Loop Structure ◽  
X Ray ◽  
Dynamic Events ◽  
Coronal Bright Points ◽  
Coronal Activity ◽  
East Limb ◽  
Coronal Structures

Data obtained by the AS&E X-ray Telescope Experiment during the first Skylab mission have revealed a variety of temporal changes in both the form and brightness of coronal structures. Dynamical changes have been noted in active regions, in large scale coronal structures, and in coronal bright points. The coronal activity accompanying a series of Hα flares and prominence activity between 0800 and 1600 UT on 10 June 1973 in active region 137 (NOAA) at the east limb is shown in Figure 1. It is characterized by increases in the brightness and temperature of active region loops and a dramatic change in the shape and brightness of a loop structure. Figure 2 shows the reconfiguration of an apparent polar crown filament cavity between 1923 UT on 12 June 1973 and 1537 UT on 13 June 1973. A ridge of emitting material which attains a peak brightness at least four times that of the surrounding coronal structures appears within the cavity during the course of the event. Typical X-ray photographs with filters passing relatively soft X-ray wavelengths (3–32, 44–54 Å) show 90 to 100 X-ray bright points (Vaiana et al., 1973). On twelve occasions in the data from the first mission, such bright points were seen to increase in intensity by two orders of magnitude in less than 4 min. Such an event is shown in Figure 3.

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