[600MRG] Ionosphere Patch Mapping

[James Hollander]

    Merv, thanks. This 600mrg post copies the technical part of my off-line thank-you email to you. 
The VK team of Loi et al. are imaging plasma ducts that can reach along geomagnetic fieldlines even into the magnetosphere high above the ionosphere, and I'd like toread more.  Another kindof ducting--between ionospheric regions or layers--that I have the least literatureabout.  And still another kind ofducting--in the troposphere--has attracted a lot of observations anddiscussion.  
  By "patch mapping" ismeant only the method of calculation I recently posted to 600mrg.  As you saw, the calculation converts timeswhen XIQ's signal was lost and re-acquired at 3 stations (SWLK9EN61, WB8ILI, WA3TTS/2) into a geographic  outline of part of a moving patch orhypothetical sky region. The patch is assumed to move as one entity, with acalculable velocity, geographically somewhere around the midpoint of theassumed mostly one-hop signal path in this case.  
   No patch altitude iscalculated, and no geophysical interpretation is required.  However, I do venture an interpretation--atraveling wave in the ionosphere. Reasons: 1) The ionosphere helps redirect outgoing RF downward to theRXs. 2) A traveling wave seems less energetic (and less demanding on the imagination) than mass transport. 3) Theestimated patch velocity lies in a range of speeds of ionospheric acousticwaves reported in the cited literature. However, any alternative interpretation ought to be considered that theevidence can reasonably also support. 
   You are correct, the phrase"patch mapping" does not come from literature I've read.  It's not triangulation in the sense ofcomparing directions of arrival or comparing signal delays.  The posted calculation does depend on havingat least three RX stations geographically spread out enough to "map"a hundred miles or more of "patch" with not-unreasonable error. Also,the RX stations are geographically close enough together to make the assumptionplausible that their receptions are arising from one same "patch"that can be somewhat outlined by the method. 630m ops are indeed fortunate to have the level of interest by enoughstations that met these conditions on July 30.   
    73, Jim H W5EST