Return-Path: Received: (qmail 22092 invoked from network); 30 Mar 2001 22:56:57 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 30 Mar 2001 22:56:57 -0000 Received: (qmail 14898 invoked from network); 30 Mar 2001 22:56:47 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 30 Mar 2001 22:56:47 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14j7im-00045B-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 30 Mar 2001 23:50:20 +0100 Received: from ruthenium.btinternet.com ([194.73.73.138] helo=ruthenium) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14j7il-000456-00 for rsgb_lf_group@blacksheep.org; Fri, 30 Mar 2001 23:50:19 +0100 Received: from [62.7.43.70] (helo=default) by ruthenium with smtp (Exim 3.03 #83) id 14j7iM-0002ja-00 for rsgb_lf_group@blacksheep.org; Fri, 30 Mar 2001 23:49:55 +0100 Message-ID: <000301c0b96b$923ec3c0$462b073e@default> From: "Alan Melia" To: "LF-Group" Subject: LF: Solar Events Date: Fri, 30 Mar 2001 23:47:44 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi all, for those of you that are interested in propagation, sunspots, solar X-ray flares and aurora (not to mention Coronal holes and CMEs ) there is an interesting article in the April 2001 issue of the Scientific American Journal. It does not have anything to say about disruption to radio propagation but it does have a lot of 'new' information about CMEs and the production of the shock-front. (It may be available on their web site, I haven't looked) It describes the injection and ejection of particles from the 'plasma-sphere' by the collision with the magnetic field of the CME. ( I think the 'plasma-sphere' they refer to is what is often called the Van Allen belts.) I believe this 'dynamo' effect could also inject energetic particles into the ionosphere, at the poles. These would be much 'hotter' than photo-dissociated ions, and so would take quite a long time to recombine (decay)....maybe as much as 10 days. The most interesting thing for me is that it 'decouples' the CME events from the X-ray flares. The older references were not able to do this not having access to data from the Geos and SOHO satellites. CMEs it seems can be caused by the same mechanism that releases an X-ray flare, but they can occur by other means without the release of X-rays. This accounts for some 'bad nights' on the CFH plots that did not seem to correlate with previous flares. SXV seems to be showing some signs of the effects of the recent CMEs as it has become very weak in daytime today. If the D-layer is heavily ionised by now it will be interesting to see if there is enhanced range from some of the weaker eastern European stations this weekend, due to daytime 'skywave'. Cheers de Alan G3NYK JO02PB Alan.Melia@btinternet.com