[TangerineSDR] Bi-Weekly HamSCI Telecon This Thursday

[Dev Joshi]

Hi HamSCI,

This week is our bi-weekly HamSCI telecon on Thursday, * Apr 15th *at 1900z
/ 3 PM Eastern.

Here is the link:
https://scranton.zoom.us/j/286316405?pwd=QWdwMlFPbDlYeXg5ZDg1dmYzeFdCUT09

If you are asked for a password, it is “hamsci”.

Dr. Vadym Paznukhov, Senior Research Scientist, at Institute for Scientific
Research, Boston College will talk about his latest research work.

Best,
Dev

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*Talk Title : Application of the mirror model to ionospheric data analysis*

                 -- Dima Paznukhov, Boston College, Institute for
Scientific Research



Abstract: A mirror model is a simple but convenient and powerful way of
modeling radiowave propagation through ionospheric plasma. It assumes a
reflection of the waves from a perfectly conducting layer (a “mirror”)
located at a certain height in the ionosphere and neglects refraction
effects in the underlying plasma. It can be efficiently used to
characterize HF wave reflections from the ionosphere as long as magnetic
field effects are not very strong. An extension of a conventional flat
mirror model is a mirror tilted at a certain angle, and a corrugated mirror
accounting for wavelike structures in the ionosphere. Experimental results
are presented that illustrate the validity and accuracy of the mirror model
approach for HF geolocation. Digisonde sounders allow measuring angles of
arrival of ionospherically reflected radio signals, from which the
ionospheric tilts are derived using the mirror model assumption. Using
several years of observations a climatological distribution of wavelike
variations in the tilt records presumed to be associated with travelling
ionospheric disturbances (TIDs) is established. Most of the observed TIDs
have their main periods of 30 min to 1.5 hours which is rather typical for
medium-scale TIDs. Direction of disturbance propagation is also analyzed
and compared to the modelled neutral wind. There are indications that
during the daytime TIDs tend to propagate in the direction opposite to the
background neutral wind. This suggests that daytime TIDs are produced by
atmospheric gravity waves originating in the lower atmosphere and
experiencing background wind filtering effect on their upward propagation.
A corrugated mirror can also be used to measure parameters of TID
disturbances under some assumptions of their characteristics. Examples of
such measurements are also presented.


Brief Bio: *Dima Paznukhov* is a Senior Research Scientist at Boston
College Institute for Scientific Research. He holds a PhD in Physics from
the University of Massachusetts Lowell (2004), and a MS in electrical
Engineering from Kharkov State Polytechnic University (1995). He has been
at Boston College since 2010, and previously was at the University of
Massachusetts Lowell Center for Atmospheric Research. He is an expert in
experimental investigation of irregular ionospheric phenomena, particularly
ionospheric storms, AGW/TID waves, sporadic ionospheric layers. He has
developed and deployed several dedicated acquisition systems for observing
TIDs with analog and digital receivers which made it possible conducting
large scale ionospheric studies.

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Dev Joshi, Ph.D., KC3PVE
Postdoctoral Research Associate
Department of Physics and Engineering
The University of Scranton
C: 617 775 9712
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