Radio frequency response of GaN-based SAW oscillator to UV illumination by the Sun and man-made source

2002 ◽  
Vol 38 (3) ◽  
pp. 134 ◽  
Author(s):  
D. Ciplys ◽  
R. Rimeika ◽  
M.S. Shur ◽  
R. Gaska ◽  
A. Sereika ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Frequency Response ◽  
The Sun ◽  
Uv Illumination

scholarly journals Induced Topological Superconductivity in a BiSbTeSe2-Based Josephson Junction

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 794 ◽  
Author(s):  
Bob de Ronde ◽  
Chuan Li ◽  
Yingkai Huang ◽  
Alexander Brinkman
Keyword(s):  
Radio Frequency ◽  
Josephson Junction ◽  
Frequency Response ◽  
Systematic Study ◽  
Bound States ◽  
Shapiro Step ◽  
Majorana Bound States ◽  
Irradiation Power ◽  
Radio Frequency Waves ◽  
High Irradiation

A 4 π -periodic supercurrent through a Josephson junction can be a consequence of the presence of Majorana bound states. A systematic study of the radio frequency response for several temperatures and frequencies yields a concrete protocol for examining the 4 π -periodic contribution to the supercurrent. This work also reports the observation of a 4 π -periodic contribution to the supercurrent in BiSbTeSe 2 -based Josephson junctions. As a response to irradiation by radio frequency waves, the junctions showed an absence of the first Shapiro step. At high irradiation power, a qualitative correspondence to a model including a 4 π -periodic component to the supercurrent is found.

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.

scholarly journals An investigation of radio-frequency radiation from the sun

1948 ◽  
Vol 193 (1032) ◽  
pp. 98-120 ◽  
Keyword(s):  
Solar Radiation ◽  
Radio Frequency ◽  
Random Noise ◽  
Internal Noise ◽  
Black Body ◽  
Local Source ◽  
The Sun ◽  
Radio Frequency Radiation ◽  
Absolute Measurements ◽  
Frequency Radiation

It has been known for some time that the sun emits radio-frequency radiation whose intensity greatly exceeds the value expected from a black-body at 6000°K. In the present paper, experiments are described in which measurements have been made of the solar radiation at frequencies of 175 and 80 Mcyc. /sec. Measurement of the small powers which can be abstracted from practical aerial systems requires special types of receiving equipment if absolute measurements are to be recorded automatically over long periods of time. An apparatus has been developed in which the output power of a local source of random ‘noise’ is automatically and continuously adjusted so as to be equal to the aerial power; in this way the receiver is used only as an indicator of balance, and errors due to variation of its gain or internal noise are eliminated. A special type of aerial has been devised which enables the solar radiation to be recorded separately from the galactic radiation, and so enables continuous observation of the sun to be made with aerials of comparatively low directivity. The results obtained on these two frequencies show that the sun normally emits radiation whose intensity corresponds to a surface temperature of the order of 10 6 °K. Large fluctuations in the intensity occur, however, and during the passage of large sunspots, equivalent temperatures as high as 10 8 to 10 9 °K have been observed. In addition to these day-to-day variations the radiation is subject to sudden brief increases of intensity lasting only for a few seconds. Measurements of the diameter of the source, by a method analogous to Michelson’s stellar interferometer, have shown that during periods of very great intensity the radiation originates in an area of the sun of the same order of size as a sunspot. This result means that equivalent temperatures of 10 9 to 10 10 °K must exist. Measurements of the polarization of the radiation have shown that during periods of increased activity the radiation is mainly circularly polarized. The present account covers the experimental methods and the results obtained up to the present time. It is hoped to consider these results theoretically in a future paper.

Radio-Frequency Energy from the Sun

Nature ◽  
1946 ◽  
Vol 157 (3980) ◽  
pp. 158-159 ◽  
Author(s):  
J. L. PAWSEY ◽  
R. PAYNE-SOOTT ◽  
L. L. McCREADY
Keyword(s):  
Radio Frequency ◽  
The Sun ◽  
Radio Frequency Energy

Bistability in the frequency response of a driven SQUID ring-radio frequency resonator system

1997 ◽  
Vol 226 (5) ◽  
pp. 275-279 ◽  
Author(s):  
R. Whiteman ◽  
J. Diggins ◽  
V. Schöllmann ◽  
G. Buckling ◽  
T.D. Clark ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Frequency Response ◽  
Resonator System

Radio frequency response of Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3O10+xsuperconducting tapes

2000 ◽  
Vol 13 (10) ◽  
pp. L15-L18 ◽  
Author(s):  
G Grasso ◽  
A Malagoli ◽  
N Scati ◽  
P Guasconi ◽  
S Roncallo ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Frequency Response
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