I have a question about the interplanetary magnetic field bt

[Isatsuki San]

Is it normal for the interplanetary magnetic field to register values 0.42 even 1 nt?

It's the first time I see that and I have that doubt 

[Jesterface23]

At 1AU it happens every once in a while when the conditions are right. Is would have a better chance of occurring during CMEs, or CIRs like the one we are in now.

[Isatsuki San]

I ask for the bt, not for the bz, here is an image before confusion

[Jesterface23]

1 hour ago, Jesterface23 said:

At 1AU it happens every once in a while when the conditions are right. Is would have a better chance of occurring during CMEs, or CIRs like the one we are in now.

52 minutes ago, Isatsuki San said:

I ask for the bt, not for the bz

Yes, Bt, total interplanetary magnetic field strength.

[Sam Warfel]

4 hours ago, Isatsuki San said:

Is it normal for the interplanetary magnetic field to register values 0.42 even 1 nt?

It's the first time I see that and I have that doubt 

It’s low, but not out of the ordinary for quiet solar activity. 

[Isatsuki San]

29 minutes ago, Orneno said:

Es bajo, pero no fuera de lo común para una actividad solar tranquila. 

oh well it seems curious to me as well

2 hours ago, Jesterface23 said:

Sí, Bt, fuerza total del campo magnético interplanetario.

 

4 hours ago, Jesterface23 said:

En 1AU sucede de vez en cuando cuando las condiciones son adecuadas. Tendría una mejor oportunidad de ocurrir durante las CME o CIR como en la que nos encontramos ahora.

oh that's fine so that's why that happens

[Sam Warfel]

3 hours ago, Isatsuki San said:

oh well it seems curious to me as well

Yes, the solar wind environment is *extremely* calm and quiet right now. Look at the solar wind speed, it dropped all the way to the 290 km/s range, very slow. 
So I’m not surprised to see weaker Bt. 

[David Silver]

@Jesterface23where /how can one track a CIR? URL please?

When did we enter this current CIR? Thank you.

[Jesterface23]

11 minutes ago, David Silver said:

@Jesterface23where /how can one track a CIR? URL please?

When did we enter this current CIR? Thank you.

Sometimes it is hard to tell when they arrive. You can track a CIR by looking at the proton density. They are pushed ahead of the CH HSSs like in the solar wind prediction models, https://www.swpc.noaa.gov/products/wsa-enlil-solar-wind-prediction. The density is high while the velocity and temperature is low.

This CIR is probably a mix of 2 CIRs starting back somewhere around 11/23 00:00Z or 05:00Z. The rise in density is a little bit noticeable and in this case there is a sharp change in the IMF.

It looks like we are in the CIR to CH HSS transition at the time of comment. The CIR/HSS transition started around 11/25 21:30Z with the velocity and temperature rise.

DSCOVR, ACE, and SOHO are all good available options to look at, and it is good to look at them all because they don't always agree.
https://www.swpc.noaa.gov/products/real-time-solar-wind
https://space.umd.edu/pm/

[David Silver]

Thank you. I thought this was the case, that we need to observe these various metrics to determine when CIR occur.
 

We hypersensitives from the thread that shall not be named have had an unpleasant week. I have noticed in past incidents that CIR can cause some of the strongest negative effects, somewhat counterintuitively, and such has been the case again this past week. The very low KP and such was not helping. Hopefully ending now. Much appreciated.

Edited November 25, 2022 by David Silver

[Jesterface23]

The more you know.