scholarly journals Evidence for Open Field Lines from Active Regions: Short Communication

1980 ◽  
Vol 91 ◽  
pp. 261-261
Author(s):  
K. V. Sheridan
Keyword(s):  
Open Field ◽  
Subject Matter ◽  
Short Communication ◽  
Active Regions ◽  
Theoretical Physics ◽  
University Of Colorado ◽  
Solar Active Regions ◽  
The Subject ◽  
Field Lines ◽  
Sydney Australia

A paper that has considerable relevance of the subject matter of this symposium is the following: “Evidence for Extreme Divergence of Open Field Lines from Solar Active Regions,” by G. A. Dulk (Division of Radiophysics, CSIRO, Sydney, Australia and Department of Astro-Geophysics, University of Colorado, Boulder, Colorado), D. B. Melrose (Department of Theoretical Physics, University of Sydney, Australia) and S. Suzuki (Division of Radiophysics, CSIRO, Sydney, Australia).

scholarly journals Low Brightness Temperature in Microwaves at Periphery of Some Solar Active Regions

2017 ◽  
Vol 54 (3) ◽  
pp. 58-67
Author(s):  
B. I. Ryabov ◽  
D. A. Bezrukov ◽  
J. Kallunki
Keyword(s):  
Brightness Temperature ◽  
Open Field ◽  
Active Regions ◽  
Source Surface ◽  
The Sun ◽  
Coronal Emission ◽  
Field Source ◽  
Wavelet Space ◽  
Solar Active Regions ◽  
Field Lines

AbstractThe microwave regions with low brightness temperature are found to overlap the regions of the depressed coronal emission and open field lines at the periphery of two solar active regions (ARs). The imaging microwave observations of the Sun with the Nobeyama Radio heliograph at 1.76 cm, the MRO-14 radio telescope of Metsähovi Radio Observatory at 0.8 cm, and the RT-32 of Ventspils International Radio Astronomy Centre in the range 3.2-4.7 cm are used. To reduce the noise in the intensity distribution of the RT-32 maps of the Sun, one wavelet plane of “à trous” wavelet space decomposition is subtracted from each map. To locate the open-field regions, the full-Sun coronal magnetic fields with the potential field source surface (PFSS) model for RSS= 1.8 Rʘare simulated. We conclude that the revealed LTRs present narrow coronal hole-like regions near two ARs and imply an extra investigation on the plasma outflow.

Evidence for Extreme Divergence of Open Field Lines from Solar Active Regions

1979 ◽  
Vol 3 (6) ◽  
pp. 375-379 ◽  
Author(s):  
G. A. Dulk ◽  
D. B. Melrose ◽  
S. Suzuki
Keyword(s):  
Magnetic Field ◽  
Open Field ◽  
Interplanetary Space ◽  
Active Regions ◽  
Type Iii ◽  
Solar Active Regions ◽  
Field Lines ◽  
Type V ◽  
Open Magnetic Field

In this paper we review the evidence on the structure of the open magnetic field lines that emerge from solar active regions into interplanetary space. The evidence comes mainly from the measured sizes, positions and polarization of Type III and Type V bursts, and from electron streams observed from space. We find that the observations are best interpreted in terms of a strongly-diverging field topology, with the open field lines filling a cone of angle ~60°.

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.

Words

PMLA ◽  
1935 ◽  
Vol 50 (4) ◽  
pp. 1320-1327
Author(s):  
Colbert Searles
Keyword(s):  
Subject Matter ◽  
Assistant Professor ◽  
The Subject

THE germ of that which follows came into being many years ago in the days of my youth as a university instructor and assistant professor. It was generated by the then quite outspoken attitude of colleagues in the “exact sciences”; the sciences of which the subject-matter can be exactly weighed and measured and the force of its movements mathematically demonstrated. They assured us that the study of languages and literature had little or nothing scientific about it because: “It had no domain of concrete fact in which to work.” Ergo, the scientific spirit was theirs by a stroke of “efficacious grace” as it were. Ours was at best only a kind of “sufficient grace,” pleasant and even necessary to have, but which could, by no means ensure a reception among the elected.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

The Taxonomic Structuring of Medical Information and its Usefulness in this Form

1965 ◽  
Vol 04 (03) ◽  
pp. 112-114 ◽  
Author(s):  
H. Zinsser
Keyword(s):  
Subject Matter ◽  
Medical Information ◽  
Central Core ◽  
Diagnostic Strategy ◽  
Programmed Instruction ◽  
Orderly Fashion ◽  
The Subject

An outline has been presented in historical fashion of the steps devised to organize the central core of medical information allowing the subject matter, the patient, to define the nature and the progression of the diseases from which he suffers, with and without therapy; and approaches have been made to organize this information in such fashion as to align the definitions in orderly fashion to teach both diagnostic strategy and the content of the diseases by programmed instruction.

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