Return-Path: Received: from mtain-dd11.r1000.mx.aol.com (mtain-dd11.r1000.mx.aol.com [172.29.64.151]) by air-de05.mail.aol.com (v127_r1.1) with ESMTP id MAILINDE051-5eb24ba00faf91; Tue, 16 Mar 2010 19:09:35 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 45B3A380000D5; Tue, 16 Mar 2010 19:09:33 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NrfrR-0000k6-AY for rs_out_1@blacksheep.org; Tue, 16 Mar 2010 23:07:41 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NrfrQ-0000jx-VL for rsgb_lf_group@blacksheep.org; Tue, 16 Mar 2010 23:07:40 +0000 Received: from mx.omskcity.com ([79.133.160.2]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Nrfr4-0007eO-RW for rsgb_lf_group@blacksheep.org; Tue, 16 Mar 2010 23:07:40 +0000 Received: from noname.nodomain.nowhere (host209.161-133-79.sotline.ru [79.133.161.209]) by mx.omskcity.com (8.13.6/8.13.6) with ESMTP id o2GN74AS019897 for ; Wed, 17 Mar 2010 05:07:08 +0600 (OMST) (envelope-from fitec@omskcity.com) Received: from localhost (fitec@localhost) by noname.nodomain.nowhere (8.8.5/8.8.5) with SMTP id WAA00255 for ; Tue, 16 Mar 2010 22:58:15 GMT X-Authentication-Warning: noname.nodomain.nowhere: fitec owned process doing -bs Date: Tue, 16 Mar 2010 22:58:15 +0000 (GMT) From: "Alexander S. Yurkov" To: rsgb_lf_group@blacksheep.org In-Reply-To: <4B9FD008.2070607@abelian.org> Message-ID: MIME-Version: 1.0 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.1.8 (mx.omskcity.com [79.133.160.2]); Wed, 17 Mar 2010 05:07:09 +0600 (OMST) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Ionospheric VLF propagation Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1d40974ba00fad4bb6 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) On Tue, 16 Mar 2010, Paul Nicholson wrote: > > For conservation of energy, it cannot be higher than > that, so that gives an upper bound. > > Then there must be the exponential factor for attenuation... Certanly exponential factor exp(-r/a) should be present. I mentioned this before. But i have no ideas how to estimate roughly (at least) parameter (length) a. Intuitively i expect a = few of 1000s km. Then exp is neglectable (about 1) at 800 km. But this should be calculated. At the earth bondary one can use Leontovich bondary condition for such calculations, it is simple and parameters are known roughly. But what to do with ionosphere boundary... To neglect dissipation in ionosphere looks not reasonable. Certanly it is solvable problem but one need to work much, particulary study literature to find any estimations of plasma parameters of D-layer, particulary free path length of electron and electron concentration for diferent height. Then Maxwell's equations to be solved. Anyway this require not couple of hours, much more. But i have very few time for this now. May be much later... To solve the problem (rather volumable problem) is nice task for physicist. I expect it was solved many years ago in book by V.L. Ginzburg. But some training is usefull anyway. If one have time...:-) Regards, Alexander/RA9MB