Solar cycle 25

[JR]



Not that you'd know it with the weather we've been having, but the current solar cycle appears to be ramping up in terms of activity, with more sunspots and bigger prominences than in previous years.  At the minimum around 2019, three quarters of days showed no sunpots.  So far this year, not long admittedly, there has been at least one every day.

The experts point out that the previous 11 year solar cycle started in the same way as the current one, but overall it did not build to a maximum that could be called spectacular.

I took a shot of current sunspots in a clear spell on the morning of 5 February 2022 at 10:27:08 (Lunt 60 f8.3/500mm and zwo asi 120 colour, stacked best 25% of 500 rather shaky video frames).  

I've made a collage of this image with the sunspot number references taken from the NASA solar dynamics observatory, as well as an SDO diagram of the magnetic field lines from the sunspots in the image, 2939 and 2940, and others .  My photo isn't quite at the proper sun rotational angle but the sunspot numbers provide the reference points (the published diagram is not updated daily, and relates to a later day with yet more sunspots). 

https://sdo.gsfc.nasa.gov/assets/img/latest/latest_2048_HMIBpfss.jpg

The interesting feature to my mind is the way the magnetic field lines join all sunspots together as a sun wide phenomenon, over massive distances, not just locally.  Sunspots often appear in pairs suggesting a bar magnet arrangement, as vaguely with 2939 and definitely with SP 2940 with one pair and a triple, but things turn out to be far more complex.

The SDO was launched in 2010 into a synchronous earth orbit.  It can observe the sun more or less continuously.  Info here

https://sdo.gsfc.nasa.gov/assets/docs/SDO_Guide.pdf

This includes the explanation of how the field lines are measured, "using the Zeeman effect to work out the polarisation of the same field line and give the magnetic field over the sun surface".  I am none the wiser but mightily impressed it can be done.

  

James

Sent from my iPad

[William Bottaci]

A late reply but thank you James for the image, and the update and background.

The sun's magnetic field, the lines breaking and recombining, is now a
major area of research as it seems to explain several events such as
flares and coronal mass ejections.
The heat ionises the hydrogen, the material therefore becomes charged,
movement due to the convection creates magnetic fields and in turn
this field moves material around. Dependent of the movement the lines
can become concentrated and this stores a lot of energy, liberated
when the field breaks, and also when it does the opposite and 'makes'.

Thanks for sharing, William

[JR]

Thanks for getting back William. The sun is a fascinating object. Perhaps this research and other similar could feature as a Society talk from an expert in the future?

James

Sent from my iPad

> On 23 May 2022, at 16:30, William Bottaci <w.bo...@gmail.com> wrote:
>
> A late reply but thank you James for the image, and the update and background.

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