Source of high speed stream?

[Sam Warfel]

For a day or so now we've been under the influence of a high speed stream (HSS).  It is a fairly decent one, with speeds in the range of 550-575km/s, which coupled with a moderately strong IMF has led to several periods of KP4 and at least one G1 (KP5) geomagnetic storm.

The thing that's got me puzzled is, where on Earth (or where on the sun, as the case may be!) is this high speed stream coming from? Usually these come from Coronal Holes, but there has been none or next to none of these on the Earth-facing disk at all recently, as far as I can tell.
Where did this HSS come from? Can they be originate in something other than a CH? Or was there a tiny CH I missed, that happened to hit us with an HSS? I thought tiny CHs weren't capable of a decent high speed stream, even if one was lucky enough to hit Earth.

There's a tiny equatorial hole on the 15th, but that's too recent to have sent off this HSS, and it only existed for one day.
As I look at the archives, it looks like the solar wind speed has just kinda been a steady ramp up since at least one CME impact on the 14th.  It was a relatively minor impact, and CMEs do not typically have a form that slowly increases the wind speed over several days, so it doesn't seem like that should be related either.

Any experts know what's going on?

[Newbie]

2 hours ago, Orneno said:

For a day or so now we've been under the influence of a high speed stream (HSS).  It is a fairly decent one, with speeds in the range of 550-575km/s, which coupled with a moderately strong IMF has led to several periods of KP4 and at least one G1 (KP5) geomagnetic storm.

The thing that's got me puzzled is, where on Earth (or where on the sun, as the case may be!) is this high speed stream coming from? Usually these come from Coronal Holes, but there has been none or next to none of these on the Earth-facing disk at all recently, as far as I can tell.
Where did this HSS come from? Can they be originate in something other than a CH? Or was there a tiny CH I missed, that happened to hit us with an HSS? I thought tiny CHs weren't capable of a decent high speed stream, even if one was lucky enough to hit Earth.

There's a tiny equatorial hole on the 15th, but that's too recent to have sent off this HSS, and it only existed for one day.
As I look at the archives, it looks like the solar wind speed has just kinda been a steady ramp up since at least one CME impact on the 14th.  It was a relatively minor impact, and CMEs do not typically have a form that slowly increases the wind speed over several days, so it doesn't seem like that should be related either.

Any experts know what's going on?

Mainly Coronal Hole related.

The geomagnetic field was quiet to minor storm level on October 15 under the influence of coronal hole effects. Solar wind speed at SOHO ranged between 434 and 642 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. 

SWPC:-

.24 hr Summary... Solar wind parameters continued under the influence of a negative polarity CH HSS. Solar wind speed ranged from 540-606 km/s. Total field ranged from 2-6 nT while the Bz component was between +5/-6 nT. Phi angle was mostly negative with deviations into a positive sector between 16/0537-1129 UTC. .

Forecast... Enhanced conditions are expected to continue through early to midday on 17 Oct due to negative polarity CH HSS influence. Waning conditions are expected by late on 17 Oct. A return to nominal levels is likely on 18-19 Oct.

Highlighted CH's pretty much earth facing. First pic is SWPC, Solen sees it a little differently, they have higher res.but the two sites rarely agree!

N.

Edited October 17, 2022 by Newbie

[Cat Perkinton]

3 hours ago, Orneno said:

For a day or so now we've been under the influence of a high speed stream (HSS).  It is a fairly decent one, with speeds in the range of 550-575km/s, which coupled with a moderately strong IMF has led to several periods of KP4 and at least one G1 (KP5) geomagnetic storm.

The thing that's got me puzzled is, where on Earth (or where on the sun, as the case may be!) is this high speed stream coming from? Usually these come from Coronal Holes, but there has been none or next to none of these on the Earth-facing disk at all recently, as far as I can tell.
Where did this HSS come from? Can they be originate in something other than a CH? Or was there a tiny CH I missed, that happened to hit us with an HSS? I thought tiny CHs weren't capable of a decent high speed stream, even if one was lucky enough to hit Earth.

There's a tiny equatorial hole on the 15th, but that's too recent to have sent off this HSS, and it only existed for one day.
As I look at the archives, it looks like the solar wind speed has just kinda been a steady ramp up since at least one CME impact on the 14th.  It was a relatively minor impact, and CMEs do not typically have a form that slowly increases the wind speed over several days, so it doesn't seem like that should be related either.

Any experts know what's going on?

I was also wondering abut this, thanks for bringing it up.

[Jesterface23]

This mainly all starts out around the 11th with CHs to the north and south. The end of it looks to be the CH facing us now.
https://drive.google.com/file/d/1KPmmV69kBq3-m-IwBLVO8c2rmn81lX-C/view

The CIR arrived some time on the 13th and the CH HSS fully transitioned on the 15th at around 23:30Z. The CH HSS arrived around the 14th 09:00Z.

Edited October 17, 2022 by Jesterface23

[Andrey M]

13 hours ago, Newbie said:

Mainly Coronal Hole related.

The geomagnetic field was quiet to minor storm level on October 15 under the influence of coronal hole effects. Solar wind speed at SOHO ranged between 434 and 642 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. 

SWPC:-

.24 hr Summary... Solar wind parameters continued under the influence of a negative polarity CH HSS. Solar wind speed ranged from 540-606 km/s. Total field ranged from 2-6 nT while the Bz component was between +5/-6 nT. Phi angle was mostly negative with deviations into a positive sector between 16/0537-1129 UTC. .

Forecast... Enhanced conditions are expected to continue through early to midday on 17 Oct due to negative polarity CH HSS influence. Waning conditions are expected by late on 17 Oct. A return to nominal levels is likely on 18-19 Oct.

Highlighted CH's pretty much earth facing. First pic is SWPC, Solen sees it a little differently, they have higher res.but the two sites rarely agree!

N.

 Sorry, but this picture has nothing to do with the current moment ☹️

[Newbie]

13 hours ago, Andrey M said:

 Sorry, but this picture has nothing to do with the current moment ☹️

Hahaha you are so right Andrey M. I was looking at the timestamp and not at the date. 

I hope you can see the funny side. I can

N.

Been on holidays too long

Edited October 18, 2022 by Newbie