Shock location and CME 3-D reconstruction of a solar type II radio burst with LOFAR
by P. Zucca et al.*

2018-10-30 285 views

Type II radio bursts are the result of shocks in the solar atmosphere and they can be observed ranging from sub-metric to kilometric wavelengths (~400 MHz to ~0.4 MHz). Coronal mass ejections initiate most of the metric type II (m-type II) bursts. The region of a CME responsible for driving the shock might be different for each event and has not yet been comprehensively identified. Multiple scenarios have been suggested, […]

Topical issue “Solar radio physics from the chromosphere to near Earth” published
by E.P Kontar and A. Nindos

2018-06-26 529 views

The 2016 CESRA workshop (http://cesra2016.sciencesconf.org) had a special emphasis on the complementarity of current and future space-based observations with ground-based radio observations. It was the place to discuss the new exciting science opportunities that arise from radio instruments such as the Atacama Large Millimeter/submillimeter Array (ALMA), the Expanded Owens Valley Solar Array (EOVSA), the Expanded Very Large Array (EVLA), the Low Frequency array (LOFAR), the Mingantu Spectral Radioheliograph (MUSER), and […]

New evidence for a coronal mass ejection driven fast drifting type II radio burst
by K. Anshu et al.

2018-04-03 611 views

Type II solar radio bursts are considered to originate from plasma waves excited by magnetohydrodynamic (MHD) shocks and converted into radio waves at the local plasma frequency and its harmonics. Type II radio bursts are mostly associated with coronal mass ejections (CMEs) and flares Nindos et al. (2008). We studied a seldom occurring high frequency type II burst on 4th Novemeber 2015, which had both fundamental and harmonic components. The […]

Source regions of the type II radio burst observed during a CME–CME interaction on 2013 May 22
by P. Mäkelä et al.*

2016-12-06 3,038 views

Occasionally the Sun ejects a pair of magnetized plasma clouds, called coronal mass ejections (CMEs), roughly into the same propagation direction in closely timed sequence. If the second CME is faster than the first one, the CMEs could either just slip through each other or they could collide and interact, when the following CME catches up the preceding one. The possibility of the CME-CME interaction was first suggested by Gopalswamy […]

Fragmented radio emission reveals a shock passing through solar active region loops
by Silja Pohjolainen, Jens Pomoell and Rami Vainio

2008-09-02 535 views

Shocks and type II bursts Radio type II bursts are observed in association with flares and coronal mass ejections (CMEs). Metric type II bursts can be observed in dynamic radio spectra as slowly drifting emission lanes, with drift rates approximately 0.1 — 1.0 MHz/s. The start frequency of metric type II bursts is usually at about 100 — 200 MHz. The mechanism behind the bursts is generally assumed to be […]

A New Wind/WAVES Type II Burst Catalog Available Online
by Nat Gopalswamy

2007-11-22 115 views

The CDAW Data Center announces the availability of a new catalog of type II radio bursts detected by the Radio and Plasma Waves (WAVES) experiment on board the Wind spacecraft and the associated coronal mass ejections (CMEs) observed by the Solar and Heliospheric Observatory (SOHO). The catalog is available at http://cdaw.gsfc.nasa.gov/CME_list/radio/waves_type2.html The catalog also contains information on the associated flares (X-ray importance and NOAA active region number). The CME sources […]

Coronal shock waves: tracking down the drivers for radio emission
by Silja Pohjolainen

2006-09-21 144 views

In the solar corona, shocks are formed when the speed of a disturbance exceeds the local magnetosonic (Alfvén) speed. At low atmospheric heights, above high-density active regions, the Alfvén velocity can drop down to a few hundred km/s, but it then rises steadily to a global maximum of about 1000 km/s near the heliocentric height of 3.5 R (see calculations in Warmuth & Mann 2005). At heights above 1.5 R […]