Aims. We investigate the physical conditions of the sources of two metric type II bursts associated with coronal mass ejection (CME) expansions with the aim of verifying the relationship between the shocks and the CMEs by comparing the heights of the radio sources and of the extreme-ultraviolet (EUV) waves associated with the CMEs. Methods. The heights of the EUV waves associated with the events were determined in relation to the wave fronts. The heights of the shocks were estimated by applying two different density models to the frequencies of the type II emissions and compared with the heights of the EUV waves. For the event on 13 June 2010 that included band-splitting, the shock speed was estimated from the frequency drifts of the upper and lower frequency branches of the harmonic lane, taking into account the H/F frequency ratio f H / f F = 2. Exponential fits on the intensity maxima of the frequency branches were more consistent with the morphology of the spectrum of this event. For the event on 6 June 2012 that did not include band-splitting and showed a clear fundamental lane on the spectrum, the shock speed was directly estimated from the frequency drift of the fundamental emission, determined by linear fit on the intensity maxima of the lane. For each event, the most appropriate density model was adopted to estimate the physical parameters of the radio source. Results. The event on 13 June 2010 had a shock speed of 590-810 km s −1 , consistent with the average speed of the EUV wave fronts of 610 km s −1 . The event on 6 June 2012 had a shock speed of 250-550 km s −1 , also consistent with the average speed of the EUV wave fronts of 420 km s −1 . For both events, the heights of the EUV wave revealed to be compatible with the heights of the radio source, assuming a radial propagation of the type-II-emitting shock segment.

Type I radio noise storms are believed to provide a diagnostic of electron acceleration in the corona. Most type I bursts appear in chains of five or more individual bursts. An analysis of the chain properties may indicate electron density, height of emission source, and magnetic-field intensity. We studied 255 chains of solar type I solar bursts recorded by the Compact Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO-BLEN) spectrograph from 30 July to 9 August 2011 in the frequency range 170 -870 MHz. Based on the morphological characteristics identified in the dynamic spectra, we determined the physical parameters for the events. The source electron density was found to be in the range 0.5 -1.6 × 10 9 cm −3 , the radial velocity of the emitting plasma varied from −1600 -1500 km s −1 , the magnetic-field strength was in the range 2.2 -3.3 G, and the height of the source ranged from 0.95 to 1.15 solar radii. The results are consistent with previously reported values.

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Aims. We report on a well-defined EUV wave observed by the Extreme Ultraviolet Imager (EUVI) on board the Solar Terrestrial Relations Observatory (STEREO) and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The event was accompanied by a shock wave driven by a halo CME observed by the Large Angle and Spectrometric Coronagraph (LASCO-C2/C3) on board the Solar and Heliospheric Observatory (SOHO), as evidenced by the occurrence of type II bursts in the metric and dekameter-hectometric wavelength ranges. We investigated the kinematics of the EUV wave front and the radio source with the purpose of verifying the association between the EUV wave and the shock wave. Methods. The EUV wave fronts were determined from the SDO/AIA images by means of two appropriate directions (slices). The heights (radial propagation) of the EUV wave observed by STEREO/EUVI and of the radio source associated with the shock wave were compared considering the whole bandwidth of the harmonic lane of the radio emission, whereas the speed of the shock was estimated using the lowest frequencies of the harmonic lane associated with the undisturbed corona, using an appropriate multiple of the Newkirk (1961, ApJ, 133, 983) density model and taking into account the H/F frequency ratio fH∕fF = 2. The speed of the radio source associated with the interplanetary shock was determined using the Mann et al. (1999, A&A, 348, 614) density model. Results. The EUV wave fronts determined from the SDO/AIA images revealed the coexistence of two types of EUV waves, a fast one with a speed of ~560 km s−1, and a slower one with a speed of ~250 km s−1, which corresponds approximately to one-third of the average speed of the radio source (~680 km s−1). The radio signature of the interplanetary shock revealed an almost constant speed of ~930 km s−1, consistent with the linear speed of the halo CME (950 km s−1) and with the values found for the accelerating coronal shock (~535–823 km s−1), taking into account the gap between the radio emissions.

RESUMO: Neste trabalho são apresentados os resultados da análise de cinco emissões solares tipo-U e tipo-J registradas pelo rádio espectrógrafo "Brazilian