Solar Sources of ``Driverless'' Interplanetary Shocks
Abstract
We identify the solar sources of a large number of interplanetary (IP) shocks that do not have a discernible driver as observed by spacecraft along the Sun-Earth line. At the Sun, these ``driverless'' shocks are associated with fast and wide CMEs. Most of the CMEs were also driving shocks near the Sun, as evidenced by the association of IP type II radio bursts. Thus, all these shocks are driven by CMEs and they are not blast waves. Normally limb CMEs produce driverless shocks at 1 AU. But some disk-center CMEs also result in driverless shocks because of deflection by nearby coronal holes. We estimate the angular deflection to be in the range 20°-60°. We also compared the influence of nearby coronal holes on a set of CMEs that resulted in magnetic clouds. The influence is nearly three times larger in the case of driverless shocks, confirming the large deflection required.
- Publication:
-
Twelfth International Solar Wind Conference
- Pub Date:
- March 2010
- DOI:
- 10.1063/1.3395902
- Bibcode:
- 2010AIPC.1216..452G
- Keywords:
-
- solar activity;
- solar corona;
- magnetic field effects;
- shock wave effects;
- astronomical observatories;
- 96.60.Q-;
- 96.60.ph;
- 96.60.Hv;
- 43.25.Cb;
- 95.45.+i;
- Solar activity;
- Coronal mass ejection;
- Electric and magnetic fields solar magnetism;
- Macrosonic propagation finite amplitude sound;
- shock waves;
- Observatories and site testing