Major Farside CME and Radiation Storm

Sept. 6, 2002: Something just exploded on the farside of the sun. NASA’s STEREO-A spacecraft recorded a magnificent full-halo CME emerging during the late hours of Sept. 5th:

A NASA model of the CME shows it heading away from Earth and directly toward Venus. This will be the second time in a week that Venus has been hammered by a significant solar storm. An earlier CME struck on Sept. 1st, probably launched by the same farside sunspot.

“This is no run of the mill event,” says George Ho of the Johns Hopkins Applied Physics Lab. “Many science papers will be studying this for years to come.”

Ho is the principal investigator for an energetic particle detector onboard Europe’s Solar Orbiter spacecraft–and he is getting a lot of data right now. Solar Orbiter just performed a close flyby of Venus (only 6420 km away) to adjust its orbit around the sun. It is in the perfect position to observe the storm.

This plot shows a wave of energetic particles washing over the spacecraft:

Above: Data from Solar Orbiter’s EPD/Suprathermal Ion Spectrograph. These are quick-look data; they have not been checked for accuracy and are subject to revision

“I can safely say the Sept. 5th event is one of the largest (if not THE largest) Solar Energetic Particle (SEP) storms that we have seen so far since Solar Orbiter launched in 2020,” says Ho. “It is at least an order of magnitude stronger than the radiation storm from last week’s CME.”

“In fact, the >10 MeV and >50 MeV particle intensity has not subsided since the beginning of the storm yesterday,” adds Ho. “This is indicative of a very fast and powerful interplanetary shock, and the inner heliosphere may be filled with these high-energy particles for a long time. I think I’ve only seen couple of these in the last couple solar cycles.”

Earth is not affected by the storm, which is happening on the opposite side of the sun. However, we may not be safe from its source. The underlying explosion almost certainly happened in the magnetic canopy of AR3088, an active sunspot that popped up on the Earthside of the sun in August. It is now transiting the farside, apparently bigger and angrier than before. The sun’s rotation will turn AR3088 toward us again in little more than a week, putting Earth back in the line of fire. Stay tuned.Solar flare alerts: SMS Text

This story was brought to you by Spaceweather.com

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