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

2018-10-30 307 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, […]

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

2008-09-02 536 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 […]

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

2006-09-21 148 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 […]