A “Chain Reaction” Explosion on the Sun

Feb. 25, 2023: A magnetic filament connected to sunspot AR3229 erupted on Feb. 24th, producing a chain reaction of events that could lead to a geomagnetic storm on Earth. The action began at 1949 UTC when the filament rose up and sliced through the sun’s atmosphere:

The violent liftoff destabilized sunspot AR3229, sparking a long duration M3-class solar flare (2030 UTC). Radiation from the flare, in turn, ionized the top of Earth’s atmosphere, blacking out shortwave radio transmissions around the Pacific Ocean: map. Mariners and ham radio operators may have noticed loss of signal at frequencies below 25 MHz for as much as an hour after the explosion.

Next, a CME emerged from the blast site. Coronagraph images from SOHO show a lopsided halo with an Earth-directed component:

Type II solar radio emissions from the leading edge of the CME suggest a departure speed of 1200 km/s (2.7 million mph). The flank of the fast-moving cloud could reach Earth on Feb. 27th. NOAA analysts are modeling the CME now, so stay tuned for a refined forecast.

There’s more: Shock waves inside the CME accelerated protons to nearly light speed, and they have already reached Earth. Our planet’s magnetic field is funneling the particles toward the poles where a second type of radio blackout is underway–a polar cap absorption (PCA) event. Airplanes flying over these regions may find that their shortwave radios won’t work due to the ionizing effect of infalling protons: map.

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Sunspot Counts Hit Their Highest Level in 9 Years

Feb. 1, 2023: In a continued sign of strength for Solar Cycle 25, sunspot counts just hit a 9-year high. This plot from NOAA shows how the monthly sunspot number skyrocketed in January 2023:

The monthly sunspot number of 144 in January 2023 was only percentage points away from topping the previous solar cycle, Solar Cycle 24, which peaked in Feb. 2014 with a monthly value of 146.

Originally, forecasters thought Solar Cycle 25 would be about the same as Solar Cycle 24, one of the weakest solar cycles in a century. Current trends suggest Solar Cycle 25 will surpass that low threshold, at least. Solar Maximum is not expected until 2024 or 2025, so it has plenty of time to strengthen further, perhaps far exceeding Solar Cycle 24. You can follow the progression here.

Extra: What made January 2023 so special? This picture says it all:

This is a composite image created by Patricio Leon of Santiago, Chile. Almost every day in January, Leon photographed the sun, and stacked the images to show the march of large sunspots across the solar disk.

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