CH HSS from a northern crown extension

[Drax Spacex]

Solar wind speed has been moderately high for the last few days, but why?  Absent CME influences or Earth-facing coronal holes, the consensus answer is a polar coronal.

SWPC agrees (2021 Nov 03 0030 UTC):

"Solar wind parameters indicated the connection to a positive polarity CH HSS from a northern crown extension."

Questions:

1) What analysis steps lead to the conclusion that this is a polar coronal hole influence?

2) What solar wind parameter values (other than high solar wind speed) indicate a connection to a positive polarity CH HSS from a northern crown extension?

3) What is a northern crown extension, is it atypical, and is it visible in EUV images?

4) How is it that solar wind from a polar coronal hole becomes Earth-effective if not Earth-directed?  Is it because the solar wind is following the sun's magnetic field lines, arcing up from the sun then down to the Earth?

[Christopher S.]

The wind/plasma data has been consistently strange, in my observations, since the CMEs over the last couple of days rolled through. It makes you wonder what reactions are occurring beyond the limits of what we can sense(with instruments, not our bodies).

Edited November 3, 2021 by Christopher S.

[3gMike]

2 hours ago, Drax Spacex said:

3) What is a northern crown extension, is it atypical, and is it visible in EUV images?

If you go to the Solar Activity / Sunspot regions page on this website you can click on the SWPC Synoptic map, which shows the current northern coronal extension. Extensions like this seem to be a fairly common occurrence. I've not been able to find a definition, but it seems to be related to latitude.

If you then take a look at the SDO images found under Solar Activity / Coronal Holes you will see that the extension is not so obvious. It makes you wonder how SWPC observes it. The SWPC website states " Coronal holes have historically been identified from He I 10830A ground-based observations."

[Jesterface23]

There was a long weak CH HSS not easily visible in SDO imagery facing Earth. If it is something that is possible, maybe it pulled the northern one south.

[Drax Spacex]

Dr. Skov answered these questions well in her informal YouTube space weather briefing tonight:

https://www.youtube.com/watch?v=xOKCsuqcYvo&t=2390s

"...when we have these polar coronal holes you'd think they're too far north to actually give Earth fast solar winds, but the way the sun's magnetic field works, the polar field actually comes down and this way (hands swooping from the sun's north to radially outward along the sun's equator), and that has to guide the solar wind."