Occultation of compact radio sources by the ion tail of Halley's Comet

Enhancements of scintillations of the compact radio sources PKS 2314+03 and 1827-360 were observed at 103 MHz and 408 MHz during 18-21 December 1985 and on 29 March 1986, respectively, when the plasma tail of Halley's Comet swept across them. At 103 MHz the RMS plasma density variation along the tail was 10 and 3.3/cu cm at 0.12 AU and 0.18 AU, respectively, as measured from the comet's position. At 408 MHz it was 1.9/cu cm at 0.036 AU. Comparison of results of these two sets of observations is presented

Lunar tidal variations in f<SUB>0</SUB>F<SUB>2</SUB> in the American zone during period of low solar activity. I. Equatorial station, Huancayo

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Multifrequency spectra of solar brightness temperature derived from eclipse observations

Changes in solar radio-brightness temperature were derived at 2.8,19.3 and 22.2 GHz from the observations of radio flux during the total eclipse of 1980 February 16. High-resolution MEM spectra of the brightness temperature fluctuations at the three frequencies showed periodicities ranging from 3.5 min to 128 min. Between 3.5 min and 14.6 min there are several periodicities of comparable significance common to the three operating frequencies. If the corresponding variations in brightness temperature are assumed to result from spatial variations in the solar radio emission, the observed periodicities imply scale sizes in the range 76000 km to 320000 km

Multi-Frequency observations of radio sun during total solar eclipse of February 16, 1980

Measurements of radio flux of the Sun duirng the total solar eclipse on February 16, 1980 were made from the Japal-Rangapur Observatory near Hyderabad, at radio frequencies of 2.8, 10, 19 and 22.2 GHz. Observations for both ingress and egress are available. Residual fluxesat totality for 2.8, 10 and 19 GHz were 23, 3.5 and 3 per cent respectively. The minimum fluxes were observed from 2 to 7 minutes prior to the mid-eclipse

Solar and interplanetary disturbances

Over the last three decades, a spate of solar wind observations have been made with sophisticated ground-based and space-borne instruments. Two highly successful space missions of the Skylab and the twin spacecraft Helios 1 and 2 have amassed an invaluable wealth of information on the large scale structure of the inner heliosphere, the solar and interplanetary magnetic field, coronal holes, interplanetary dust, solar windflows, etc.Solar and interplanetary propagating phenomena have been extensively studied during the last two decades. Very recently, a new simple model based on results from

Polarization characteristics of a group of spectral type III solar radio bursts at 25 MHz recorded on 14 July 1969

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Polarization Characteristics of a Group of Spectral Type III Solar Radio Bursts at 25 MHz Recorded on 14 July 1969

116-119A group of spectral type III solar radio bursts were recorded 0.11 J 4 July1969 by a time-sharing polari-meter which had a half-power bandwidth of ± 10 kHz and a time-constant of 1 sec. The dynamic spectra of this event showed super-position of the group of type III bursts on a continuum background radiation. With the help of the polarization parameters, namely, axial ratio, polarization degree and orientation angle, measured at 25 MHz, it is proposed that the burst and background components of radiation originated in different source regions

Flare-time sudden enhancements of low frequency field strength and associated meter wave solar radio bursts

A number of meter wavelength solar radio bursts of spectral Type-III have been observed by means of a solar radio spectroscope (40-240 MHz) simultaneously with sudden enhancements of low frequency (164 KHz) field strength (SES's) of Radio Tashkent which are known to take place due to the enhancements of D-layer ionization caused by flare-time solar X-rays. The association between the solar X-ray flares as detected by the SES's and the Type-III meter-wave solar bursts is discussed. It is found that the association of SES's and meter wave solar bursts, which implies the ejection of flare-time electrons towards the photosphere as well as corona, is about 72%

New microstructure of decametre solar radio bursts

The fine structure of a variety of decametre solar radio bursts obtained with high temporal and frequency resolution spectrographs provides valuable information on the generation mechanisms of these bursts together with the physical conditions in the corona. Earlier observations1-10 of solar radio bursts in the decametre region have revealed some types of fine structure bursts, drift pairs and split pairs being examples of fine temporal and frequency structure bursts respectively