Solar activity is low, but the quiet is unlikely to persist. There are three sunspots with unstable magnetic fields capable of strong eruptions: AR2108, AR2109, AR2113. NOAA forecasters estimate a 75% chance of M-flares and 15% chance of X-flares on July 10th.
Forecasters expected a solar flare today, and indeed one has occurred. But it came from an unexpected source. Emerging sunspot AR2113 showed that it is capable of strong flares with an M6-class eruption at 1630 UT on July 8th. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash:
Ionizing radiation from the flare briefly disturbed the propagation of shortwave radio transmissions on the dayside of Earth, but conditions have since returned to normal. The impulsive flare might have produced a coronal mass ejection (CME); if so, the storm cloud is almost certainly not heading toward Earth. For now, this sunspot is too far off the sun-Earth line to produce geoeffective CMEs.
QUIET WITH A CHANCE OF FLARES: Solar activity is low, but the quiet is unlikely to persist. There are three sunspots with unstable magnetic fields capable of strong eruptions: AR2108, AR2109, AR2113. NOAA forecasters estimate a 75% chance of M-flares and 15% chance of X-flares on July 10th.
RADIO STATIC FROM THE SUN: The M6-flare of July 8th had a noisy side-effect. It caused a roar of static to issue from the loudspeakers of shortwave radios on Earth. In New Mexico, amateur radio astronomer Thomas Ashcraft recorded the sounds:
“The M6.5 flare from sunspot AR2113 generated a complex mix of Type II and Type IV solar radio emissions,” says Ashcraft. “This two minute audio sample, recorded in stereo at the frequencies of 23 MHz and 21 MHz, captures the dynamic character of the bursts.”
Radio bursts such as these are sparked by shock waves moving through the sun’s atmosphere. Set in motion by flares, these shock waves excite plasma instabilitties that emit static-y radio waves. Becase there are a whole variety of plasma instabilites, there is a corresponding variety of radio burst types. Ashcraft recorded a mixture of Type II and Type IV.
ENLIL solar wind model:
C2+ Flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR|
July 6-8: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
A trans equatorial coronal hole (CH626) was in an Earth facing position on July 5.