Radio-Frequency Radiation from the Quiet Sun

1950 ◽  
Vol 3 (1) ◽  
pp. 34 ◽  
Author(s):  
SF Smerd
Keyword(s):  
Radio Frequency ◽  
Solar Atmosphere ◽  
Apparent Temperature ◽  
Coronal Temperature ◽  
Uniform Temperature ◽  
Radio Frequency Radiation ◽  
The Earth ◽  
Equivalent Measure ◽  
Limb Darkening ◽  
Frequency Radiation

The equation of transfer of radiation is used in a ray treatment of radio-frequency radiation from the solar atmosphere in the absence of solar activity. The chromosphere and the corona are represented as regions of uniform temperature. However, a range of temperatures is considered in order to allow for uncertainties in the temperature distribution in the solar atmosphere. The intensity distribution across the solar disk is shown to depend significantly on the coronal temperature. Both limb-brightening and limb-darkening can occur but are appreciable only when the corona is optically thin, yet not transparent. A measure of the size of the radio-frequency disk is obtained in terms of the size of the optical disk. The apparent temperature (an equivalent measure of the flux density at the earth) is found to reach a maximum as a function of frequency for each coronal temperature and as a function of coronal temperature for each frequency. Within the limits of experimental error all observed apparent temperatures fall within the range of theoretical values corresponding to chromospheric temperatures from 104 to 3 X 104 �K. and coronal temperatures from 2.5 X 105 to 3 X 106 �K. The effects of a possible general magnetic field of the sun are estimated in selected cases and found to be small in relation to those due to the uncertainties in the temperature of the solar atmosphere.

scholarly journals The generation of radio-frequency radiation in the sun

1948 ◽  
Vol 195 (1040) ◽  
pp. 82-97 ◽  
Keyword(s):  
Radio Frequency ◽  
Electron Temperature ◽  
Electric Fields ◽  
Solar Atmosphere ◽  
Solar Disk ◽  
Black Body ◽  
The Sun ◽  
Radio Frequency Radiation ◽  
Circularly Polarized ◽  
Frequency Radiation

Measurements of the radiation emitted by the sun at radio-frequencies have shown that the intensity greatly exceeds the value associated with a surface temperature of 6000° K. Under normal conditions the radiation, which appears to be randomly polarized, has an intensity which corresponds to the radiation from a black-body source subtending the same solid angle as the solar disk and at a temperature of about 10 6 °K. During the presence of sunspots very much more intense radiation is emitted by small areas of the solar disk; the intensity at these times corresponds to radiation from a source at a temperature of 10 9 to 10 10 °K, and the radiation is circularly polarized. The experimental results are considered theoretically in this paper, and it is concluded that the radiation in both cases arises from the acceleration of electrons in the solar atmosphere. It is suggested that by the action of the permanent magnetic field of the sun and the non-uniform rotation of the surface matter, a high potential difference is developed between the poles and the equator. Under normal conditions this potential can only produce small discharge currents through the solar atmosphere, although the electric field produced may be sufficient to maintain a mean electron temperature of 10 6 to 10 8 °K in the levels likely to emit radio-frequency radiation. During the presence of sunspots much more intense electric fields can be made available in the solar atmosphere, and in the neighbourhood of the sunspots electron temperatures of the order of 1010 °K should be maintained. A high-temperature electron gas can only radiate appreciably at those frequencies at which it absorbs well. An application of the magneto-ionic theory to the solar atmosphere above a sunspot shows that there are several regions capable of absorbing radiation at each frequency. For one of these regions the absorption (and therefore the radiating power) is very great, but radiation emitted by the region can only be propagated towards the centre of the sun. This region cannot therefore be responsible for the high-intensity radiation associated with sunspots, although the asymmetrical flow of energy from the region must produce an outward radiation pressure; this pressure may be of importance in accounting for the elevation of matter in the solar atmosphere above sunspots. Two other regions have a high absorption (each region absorbing one of the two circularly polarized components) and radiation from both regions can escape from the sun. Owing to the differences of radiating power and electron temperature in the two regions, it is likely that the intensities of the two emitted waves will be different. The radiation which is observed on the earth will therefore appear circularly polarized, the sense of the polarization corresponding to that of the most intense wave.

Health Risks of Electromagnetic Fields. Part II: Evaluation and Assessment of Radio Frequency Radiation

2003 ◽  
Vol 31 (3) ◽  
pp. 197-254 ◽  
Author(s):  
Riadh W. Y. Habash ◽  
Lynn M. Brodsky ◽  
William Leiss ◽  
Daniel Krewski ◽  
Michael Repacholi
Keyword(s):  
Radio Frequency ◽  
Electromagnetic Fields ◽  
Health Risks ◽  
Radio Frequency Radiation ◽  
Frequency Radiation ◽  
Evaluation And Assessment

Nonmonotonic superconducting transitions in mesoscopic Al structures induced by radio-frequency radiation

1996 ◽  
Vol 53 (17) ◽  
pp. 11332-11335 ◽  
Author(s):  
C. Strunk ◽  
V. Bruyndoncx ◽  
C. Van Haesendonck ◽  
V. V. Moshchalkov ◽  
Y. Bruynseraede ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Radiation ◽  
Frequency Radiation ◽  
Superconducting Transitions

scholarly journals Analysis of the Cellular Stress Response in MCF10A Cells Exposed to Combined Radio Frequency Radiation

2012 ◽  
Vol 53 (2) ◽  
pp. 176-183 ◽  
Author(s):  
Han-Na KIM ◽  
Na-Kyung HAN ◽  
Mi-Na HONG ◽  
Sung-Gil CHI ◽  
Yun-Sil LEE ◽  
...  
Keyword(s):  
Stress Response ◽  
Radio Frequency ◽  
Cellular Stress ◽  
Cellular Stress Response ◽  
Radio Frequency Radiation ◽  
Mcf10a Cells ◽  
Frequency Radiation
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