March 24, 2023 Auroras

Chippewa National Forest

This was the best event I've seen in a long time. It was probably a combination of a weak, stealthy coronal mass ejection (CME) and a high speed stream of solar wind. It may have been more a result of the CME. The magnetic field in the solar wind was hovering around 20 nT in strength, and it was pointed mostly south with perhaps 12 hours with values a couple either side of -15 nT. I tried not to look at solar wind data too much during the day because when Bz is negative during the day, there's often nowhere for the solar wind magnetic field vector to point other than farther north. I figured the same thing would happen today, but when sunset occurred with Bz still around -14 nT, I prepared to go out and shoot auroras. Conditions were ideal-- not a cloud in the sky-- and we had just a crescent new moon!

I've always got a lot of stuff to do, and I was trying to get caught up at home after being out of town for nearly three weeks. I still wanted to get some exercise, so I skied in the evening after work, returned home, and cooked some dinner. During dinner, I popped my head outside, occasionally, to check for auroras. Frequent checks revealed nothing very bright. The sky continued to darken without any definite bands of auroras showing up, but eventually, I could see a very broad, diffuse band of green pretty high in the northern sky. As the twilight continued to fade, I could see that this faint green extended overhead and maybe even to the south, but the southern limit was somewhat ambiguous and washed out by the city lights. I decided to get out of town for better contrast.

On my way out, I decided to stop at the boat landing a couple blocks to my north. I wanted to catch the crescent moon with, perhaps, a band of auroras passing through it. This spot was in town, but the auroras were getting brighter and more definite.

Auroras over the Mississippi River.

The auroras were bright enough to be seen in town. The band gradually faded through the ecliptic plane.

A corona.

Auroras on Orange Lake Road.

Auroras on Orange Lake

Auroras with fog.

Auroras over the Orange Lake island.

Auroras over white pines.

Orion hunting the auroras.

Looking back to the east as the oval begins to reconsolidate.

The band is consolidating.

Further consolidation.

Further consolidation.

The auroral band is now pretty intense and compact.

A substorm begins.

A substorm begins.

A substorm begins.

The band is consolidating.

The band is consolidating.

The band is consolidating.

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