Author Topic: complex ejecta  (Read 2116 times)

_cj_

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complex ejecta
« on: August 03, 2011, 08:01:09 pm »
hi all ...could i have some help here please

i'm just trying to get my crystal ball out and guess the geo effect of the recent two cme's on aug 2nd and 3rd.

1) does the fact that the cme's originated from the negative polarity secition of the sun mean that they will have a high negative bz component - therefore greater geo effect ?
2) why when two CME's merge and form a complex ejecta does the southward bz component tend to increase ?
3) the predicted IMF is northward for the 5th and 6th. does this mean there will be less of a geo effect ?

Regards,

alex

ChrisScott

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Re: complex ejecta
« Reply #1 on: August 03, 2011, 10:32:05 pm »
Hi Alex,

All good questions. While there may be a loose statistical connection between the orientation of the magnetic field from which the CME erupted, such things are very complex and this polarity may nit be preserved at earth. My boss likens it to a slinky spring erupting into space. Ad it expands, it twists and uncoils and it is very hard to predict which part will eventually hit Earth. As for the southward component intensifying when two CMEs interact, this is probably just an intensification of what is already there. I bet there are examples of interacting CMEs where the northward component was enhanced too. How many such interacting CMEs have been observed however is probably not more than a handful. That's why projects like solar stormwatch are so helpful in building a statistical picture of CMEs

Thanks for your time, efforts and enthusiasm,

Chris.

_cj_

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Re: complex ejecta
« Reply #2 on: August 04, 2011, 12:47:07 am »
hi chris - many thanks for the reply

in paper Noe Lugaz 2007 Complex Ejecta at L1 summarises during SC23 a significant fraction of the largest Bz periods were that of the interaction of a CME with either a preceding event or with a stream of high speed solar wind.  Citations including Xie et al 2006.. The theory being that such events tend to produce extended and extreme periods of southward Bz.

The suggestion being that this is more than just the combined components of the CME's themselves.

I suppose its just a theory

Regards,

alex