Friday, 29 September 2017

In The Shadow of Giants - 29th September

Despite a different numbering system when an active region rounds the solar limb, these are the same spots and active regions that put on a show with X class flares just 3 weeks ago.  Diminished and magnetically much quieter with stable magnetic fields, these sunspots hold little promise of solar flares however continue to put on a good show for observers world wide as we get ever closer to solar minimum.  Why are we getting these spots in the declining phase of the cycle?  Opposing bands of magnetic activity either side of the equator are violently interacting producing the activity we currently see.  How long will this last for?  Maybe another 11 months before we head into a solar winter before the next cycle starts in a couple of years...

Sunday, 24 September 2017

Return of a Monster & Increased Chances of Aurora? 24th September

Our sun is quiet again in white light, with a medium sized but unassuming single spot visible that has little chance for flaring.  However looking down in the extreme ultra violet with the Solar Dynamics Observatory things show a different picture.  A large coronal hole extending from the suns northern polar regions is now geo-effective, which coupled with a co-rotating interactive region - the boundary between slow and fast moving regions of solar wind means there is a greater risk of auroral activity in the Earths polar regions.  

On the suns eastern limb (left hand side) there are coronal loops visible rotating around the edge of our star; these are from our monster sunspot grouping from a couple of weeks ago responsible for those huge x-class flares.  Will be interesting to see how it has developed on it journey around the back side of sun in the days ahead.

Tuesday, 19 September 2017

A Wolf in Sheep Clothing - 19th September

Just 2 weeks ago we had the largest solar flare for a decade and large active regions keeping solar observers pleasantly occupied in the declining phase of the solar cycle.  Now the face of the sun is virtually blank in white light, with only one small decaying active region.  You would be mistaken in thinking this means the sun is quiet; looking in ultra violet wavelengths with the Solar Dynamics Observatories AIA imaging rig reveals a large coronal hole is visible. These are the dark patches on the solar disk on the right, and their open magnetic field lines means that the solar wind flows freely from these regions.  As they are geo-effective it means the solar wind has been interacting with the magnetic field lines of our own planet and has been producing some great aurora in our polar regions.  It just shows that just because the sun might appear quiet in white light it doesn't mean it is actually being quiet!

Tuesday, 5 September 2017

New Active Regions - 5th September

Things have been busy of late not leaving much time for solar observing or updates to my website.  I have been out in the States on holiday to observe the total solar eclipse.  I've got a lot of pictures which at the moment i'm working through processing, initial results are promising and i'm working on an animation of the whole event along with a report.  In the mean time our star is showing a pleasing amount of activity with active large sunspot genesis with large flares.  This is a result of Band - Band interaction (after McIntosh et al) where bands of deep magnetic flux associated with the declining phase of the solar cycle get ever closer at lower latitudes towards the solar equator.  These bands have opposite magnetic polarity, opposite helicity, and, because they are in different hemispheres different Coriolis forces.  As a result of all these opposing factors we should anticipate that we have dynamic, fast forming and potentially violent active regions.  Which, is exactly what we see at the moment.  Incidentally, when you consider the Carrington event in 1859 this happened in the declining phase of solar cycle 10, at exactly the same point we are no in cycle 24, maybe we will get a repeat event this cycle?  Certainly worth looking out for!