scholarly journals An Estimate of the Density and Motion of Solar Material from Observed Characteristics of Solar Radio Outbursts

1953 ◽  
Vol 6 (1) ◽  
pp. 67 ◽  
Author(s):  
Hari K Sen
Keyword(s):  
Radio Frequency ◽  
Radio Wave ◽  
Dispersion Equation ◽  
Solar Radio ◽  
Particle Density ◽  
Frequency Range ◽  
Radio Frequency Radiation ◽  
Charge Interaction ◽  
Solar Material ◽  
Frequency Radiation

The theory of radio wave generation by multistream charge interaction (Feinstein and Sen 1951) is extended and applied to the observations made by Australian workers (Wild 1950) of the spectrum of outbursts of solar radio-frequency radiation in the frequency range 70?130 Mc/s. The dispersion equation is derived as a function of the velocity of solar material erupting into a static corona and of the temperatures and densities of the material and the corona. The application of the dispersion equation to the Australian data (loc. cit.) enables an estimate to be made of the velocity (?500 km./s.) and the particle density (?108 cm.?3) of the moving solar material.

scholarly journals 60. Relation between optical solar features and solar radio emission

1957 ◽  
Vol 4 ◽  
pp. 327-333
Author(s):  
H. W. Dodson
Keyword(s):  
Radio Emission ◽  
Radio Frequency ◽  
Research Council ◽  
Solar Radio ◽  
National Research Council ◽  
Solar Radio Emission ◽  
Radio Frequency Radiation ◽  
Cornell University ◽  
Frequency Radiation

During the last five years, we at the McMath-Hulbert Observatory have been attempting to determine the characteristics of radio-frequency radiation associated with certain of the transient solar features that we normally observe on monochromatic spectroheliograms or in integrated light. We have had the privilege of using the original 200 Mc./s. records at Cornell University and the 2800 Mc./s. records at the National Research Council in Ottawa.

Solar Radio-Frequency Emission from Localized Regions at Very High Temperatures

1951 ◽  
Vol 4 (2) ◽  
pp. 131
Author(s):  
JH Piddington ◽  
HC Minnett
Keyword(s):  
Radio Frequency ◽  
Solar Radio ◽  
Thermal Emission ◽  
Thermionic Emission ◽  
Magnetic Data ◽  
Radio Frequency Radiation ◽  
Sunspot Data ◽  
Polarization Characteristics ◽  
Frequency Radiation ◽  
Three Components

Solar radio-frequency radiation is analysed into three components ; a basic steady component B, a slowly varying component S, and various forms of more or less rapid fluctuations called the X component. The spectra of all three components are drawn between 600 and 24,000 Mc/s., and suggested extensions to lower frequencies are discussed. The properties of the S component are described in some detail ; these include correlation with sunspot data, polarization, and the location of the sources of origin. Evidence is presented in favour of generation by thermal processes. It is suggested that the S component is due to thermal emission from localized regions at temperatures of about 107 �K., often in the vicinity of sunspots. The radiation from a model hot region is examined in detail and the emission spectrum and polarization characteristics are derived. The results are found to compare reasonably with observation. Thermionic emission of electrons and protons would probably occur from the hot regions. These particles would travel to the Earth with average velocities of a few hundred kilometres per second and may be identical with the slow corpuscular radiation whose presence is deduced from terrestrial magnetic data.

Observations of the Spectrum of High-Intensity Solar Radiation at Metre Wavelength. II. Outbursts

1950 ◽  
Vol 3 (3) ◽  
pp. 399 ◽  
Author(s):  
JP Wild
Keyword(s):  
Solar Radiation ◽  
Magnetic Storm ◽  
Solar Flares ◽  
High Intensity ◽  
Solar Radio ◽  
Dynamic Spectrum ◽  
Spectral Features ◽  
Frequency Range ◽  
Radio Frequency Radiation ◽  
Frequency Radiation

Observations are described of the spectrum of outbursts of solar radio-frequency radiation in the frequency range 70-130 Mc/s. In accordance with Part I of this series, an " outburst " is defined as a burst having a particular type of " dynamic " spectrum, characterized by a drift of spectral features, with time, towards the lower frequencies at a rate of the order of � Mc/s. per second. The observed outbursts are shown to have a close connexion with solar flares and their geophysical accompaniments. �� The spectra are tentatively interpreted in terms of the motion of a physical agency in the solar atmosphere. The possible identification of the agency with " surge " prominences and the corpuscular streams that cause a type of terrestrial magnetic storm is discussed. It is shown that the evidence is quite consistent with the hypothesis that the agency corresponds to the magnetic storm particles.

Galactic Radiation at Radio Frequencies. II. The Discrete Sources

1950 ◽  
Vol 3 (2) ◽  
pp. 234 ◽  
Author(s):  
GJ Stanley ◽  
OB Slee
Keyword(s):  
Radio Frequency ◽  
Crab Nebula ◽  
Wave Length ◽  
Frequency Range ◽  
Radio Frequency Radiation ◽  
Short Period ◽  
Background Continuum ◽  
The Crab Nebula ◽  
Observational Techniques ◽  
Frequency Radiation

An account is given of observations on a number of discrete sources of radio- frequency radiation, together with a brief description of the observational techniques used in their detection, and of the methods employed to determine their positions and angular extent.Noise spectra of four of the more intense sources have been measured over a frequency range of 40-160 Mc/s. : in three cases the change of intensity with wave- length is found to be greater than that of the background continuum, and in one case less. Two of the sources have been provisionally identified with astronomically rare objects, the Crab Nebula and N.G.C. 5128.Finally, the short period fluctuations in the intensity of some of the sources, notably that in Cygnus, are discussed. Evidence is presented which, contrary to previous views, suggests that these fluctuations are of terrestrial rather than of extra-terrestrial origin.

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