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<p class="MsoNormal">Dear CEDAR community,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The Arecibo Observatory Colloquium Series presents on September 29, 2020 2:00PM (AST) the talk:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">"The Physics of Incoherent Scatter with Application to the Understanding of the Plasma Line Spectrum with Narrow Peaks in the Electron Velocity Distribution Function" by Dr. Michael Sulzer from the Arecibo Observatory – UCF, Space and Atmospheric
Sciences group, Arecibo, Puerto Rico, US. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The colloquium will be streamed via Zoom <a href="https://ucf.zoom.us/j/97529242519">
(https://zoom.us/)</a> or join by phone: +1 929 205 6099, conference ID: 975 2924 2519. Further information can be found at the
<a href="https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.naic.edu%2Fpkg%2Fwebutils%2Fseries%2F%23.%2Fpages%2Fblog%2Fphysics-of-incoherent-scatter.html&data=02%7C01%7CJens.Lautenbach%40ucf.edu%7C398d1563dbfe4677b0c408d85ff6ad11%7Cbb932f15ef3842ba91fcf3c59d5dd1f1%7C0%7C0%7C637364860373177112&sdata=7Re8R%2F1pHVMpAvAGXXqAvrq0GLW0YI4mpcfY%2FwzHjPU%3D&reserved=0">
Colloquium Series Website</a>. If you like to join the Arecibo Observatory Colloquium mailing list please see this
<a href="https://areciboobservatory.us4.list-manage.com/subscribe?u=3057031f1c6bb49feeefdf63d&id=a7d471a7b5">
page</a>.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Abstract:<o:p></o:p></p>
<p class="MsoNormal">Incoherent scatter is a very useful diagnostic of the ionospheric plasma. A theoretical description of the scattered spectrum has been available for several decades, describing all the features, ion, plasma, and gyro lines, including the
possibility of both Maxwellian and non-Maxwellian particle velocity distributions. Recently Djuth and Carlson (2018) identified features in the plasma line spectrum that they convincingly attributed to narrow peaks in the electron velocity distribution function
caused by the solar ionizing EUV radiation. The observed features had unexpected narrow valleys in the spectrum as well as peaks, and all the features had unexpected frequency locations. However, the equations describing the incoherent scatter spectrum do
predict the observed behavior of these features, but this alone is not completely satisfying.<o:p></o:p></p>
<p class="MsoNormal">In this talk we review the physical principles of incoherent scatter, considering in particular two limiting cases, first with the radar looking along the earth's magnetic field, and second with very high gyro frequency. Then we show that
the characteristics of these observed features are, from this point of view, expected.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Dr. Jens Lautenbach<o:p></o:p></p>
<p class="MsoNormal">Observatory Scientist<o:p></o:p></p>
<p class="MsoNormal">Arecibo Observatory - University of Central Florida<o:p></o:p></p>
<p class="MsoNormal">Space & Atmospheric Sciences<o:p></o:p></p>
<p class="MsoNormal">HC-3 BOX 53995<o:p></o:p></p>
<p class="MsoNormal">Arecibo, Puerto Rico 00612<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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