The Cambridge IPS survey at 81.5 MHz

Search for a Compact Scintillating Component in SNR 3с58 at Decameter Wavelengths

“…В работе [10] сооб-щалось о регистрации излучения компактного мер-цающего радиоисточника в ОСН 3С58 на часто-те 102 МГц с потоком (1 0.5) ± Ян. Другие авто-ры не подтвердили наличие мерцающего радио-источника в этом ОСН на частоте 81.5 МГц [11]. Возможно, это говорит об увеличении угловых размеров компактного источника вследствие рассеяния на неоднородностях среды.…”

Reconstructing CME Structures from IPS Observations Using a Phenomenological Model

“…In practice, as we show below, it is necessary only to measure S which is advantageous as S is much more difficult to determine owing to confusion (Scheuer, 1957) and to the fact that many radio sources have a compact scintillating component embedded in a more diffuse non-scintillating component. Provided that the phase variations are small compared with one radian, the level of scintillation gives a measure of the integral of N e along the line of sight (Readhead, Kemp, and Hewish, 1978). Houminer and Hewish (Houminer, 1971;Houminer and Hewish, 1972) showed that variations in scintillation levels could be correlated with structures in the solar wind.…”

“…Within that area, it was possible to identify 2246 sources suitable for space weather measurements (note that this is rather more than the number of sources listed in the IPS catalogue (Purvis et al, 1987) which was generated from the same dataset, because for these purposes it does not matter if a deflection is due to a single source or the superposition of multiple sources). This grid is shown in Right Ascension and Declination (of date) coordinates in Figure 1.…”

“…The Thomson scattering integrals however must be replaced by the IPS integral as described by Readhead, Kemp, and Hewish (1978), Kemp (1979), and . From these we have…”

“…where: z ≡ the distance from the Earth towards the source (note that this differs from the usage of Readhead, Kemp, and Hewish (1978) and Kemp (1979) who use distance from the point of closest approach to the Sun). h ≡ the source-size term, that is the reduction in scintillation index from the value for a point source: h 2 = 2z 2 θ 2 0 /a 2 .…”