Solar Type II Radio Bursts Recorded by the Compound Astronomical Low-Frequency Low-Cost Instrument for Spectroscopy in Transportable Observatories in Brazil

Assessing the spectral characteristics of band splitting type II radio bursts observed by CALLISTO spectrometers

“…The average and median of the magnetic field are 1.0 G and 0.8 G, respectively. This result is in good agreement with the ranges reported in previous studies (see Gopalswamy et al, 2012;Cunha-Silva et al, 2014;Vasanth et al, 2014;Kishore et al, 2016;Lata Soni et al, 2021). In Fig.…”

“…The mean and median of the CME/shock speeds estimated from the low-frequency type II radio bursts provided by CALLISTO ground stations are 582 km/s and 551 km/s, respectively. It is noteworthy that this result is consistent with previous studies conducted by Ramesh et al, (2010);Cunha-Silva et al, (2014), who analyzed type II radio bursts sourced from CALLISTO (Brazil) and Gauribidanur radioheliograph (GRH, India) stations and reported that the CME/shock speeds are in the range of 452-1389 km/s and 487-974 km/s respectively.…”

Solar radio bursts observations by Egypt- Alexandria CALLISTO spectrometer: First results

“…The estimated electron density across the shock lies between 1.420 × 10 8 and 3.2996 × 10 7 cm -3 , respectively. It is worthy to note that this range is consistent with earlier findings on electron densities (see Cunha-Silva et al, 2014;Alielden, 2019;Minta et al, 2022). From Fig.…”

Well-defined EUV wave associated with a CME-driven shock

“…where N S = 5.14 × 10 9 cm −3 and A =μGM S /k B T , in which G is the gravitational constant, M S the mass of the Sun, k B the Boltzmann constant, the mean molecular weightμ has a value of 0.6, and T = 1.0 × 10 6 K. The radial speed [dR/dt] of the type-II-emitting shock segment in the corona, estimated using an appropriate multiple [n] of the Newkirk (1961) density model applied to the lowest frequencies of the harmonic emission, which are associated with the undisturbed corona, is given by (Cunha-Silva et al 2014):…”

“…The longest known signatures of shocks in the solar corona are the type II bursts (Payne-Scott et al 1947), which are narrowband slow-drift emissions observed in radio dynamic spectra, produced by plasma oscillations caused by the propagation of a fast-mode magnetohydrodynamic (MHD) shock through the solar corona (Nelson & Melrose 1985). The radio emission is observed at multiples of the electron plasma frequency, given by f p = 8.98 × 10 −3 √ N e [MHz], in which N e [cm −3 ] is the electron number density, primarily at the fundamental and second harmonic emissions, and sometimes at the third harmonic emission (see, e.g., Zlotnik et al 1998;Cunha-Silva et al 2014).…”