THE BEAMING STRUCTURES OF JUPITER’S DECAMETRIC COMMON S-BURSTS OBSERVED FROM THE LWA1, NDA, AND URAN2 RADIO TELESCOPES

On 2015 February 21, simultaneous observations of Jupiter's decametric radio emission between 10 and 33 MHz were carried out using three powerful low-frequency radio telescopes: the Long Wavelength Array Station One in the USA, the Nançay Decameter Array in France, and the URAN2 telescope in Ukraine. We measured the lag times of short-bursts (S-bursts) for 105 minutes of data over effective baselines of up to 8460 km by using cross-correlation analysis of the spectrograms from each instrument. Of particular interest is the measurement of the beaming thickness of S-bursts, testing if either flashlight- or beacon-like beaming is emanating from Jupiter. We find that the lag times for all pairs drift slightly as time elapses, in agreement with expectations from the flashlight-like beaming model. This leads to a new constraint of the minimum beaming thickness of 2farcs66. Also, we find that most of the analyzed data abound with S-bursts, whose occurrence probability peaks at 17–18 MHz

New decameter radiopolarimeter URAN-2

The description of the new decameter radiopolarimeter is submitted. It is created based on the phased array URAN-2, which is the greatest decameter array in the world after UTR-2, having the effective area about 30 000 m2, consisting of 512 broadband dipoles and working at frequencies from 10 up to 30 MHz. Polarimeter works at the central frequency of 24.75 MHz in a band of 10 kHz and 0.3 kHz. It provides reception of circular polarization waves by the horizontal crossed dipoles from any direction. Its sensitivity is ≈100 Jy. With the URAN-2 radiopolarimeter polarizing characteristics of a sporadic radio emission of the Sun (bursts of II and III types), and Jupiter (L- and S-bursts) are investigated. The obtained data will consist well with the results derived in adjacent frequency ranges. At research of the radio emission of Cyg A and Cas A the essential fluctuations of a degree of circular polarization (Stokes V parameter) of these sources radiations are found. This is caused, presumably, by ionosphere inhomogeneity. It is unique radiopolarimeter really working on so low frequencies. The URAN-2 radiopolarimeter organically supplements unique Ukrainian system of URAN decameter radio telescopes

On Polarization of Solar Decameter Spikes

In the present paper an analysis of the polarization properties of the solar decameter spikes is performed. We found that decameter spikes can possess both left and right circular polarization which changes from 0 up to 100% with an average value 50%.status: publishe