Indeed very interesting reading. Thanks!
Since Ed @DD5LP wrote this in the Propagation report thread (Propagation Report. - #2 by DD5LP)
“This weekend however with have a large CME arrived from the Sun and the K Index here is already at 5 (storm level) and will likely stay that high until late tomorrow (Sunday).”
I’ve found this to be the most likely reason for the backscatter event I found on Jan 15th, particularly after reading the following on the document shared by Andy:
"the source of backscatter ion clouds are generated within the auroral ovals and are formed during periods of high geomagnetic field disturbances. During such disturbances, the ions are able to escape the high velocity convection currents because of sudden shifts in the Earth’s magnetic field which normally trap these ion convection currents to the polar regions.
From the seven years of data collected, backscatter was observed more frequently during the winter season. It is easy to show why this is expected if backscatter is the result of charge escaping the auroral ovals during geomagnetic disturbances. During the winter season, the ionosphere is observed at higher altitudes where the auroral ovals exist with larger radii"
And this final paragraph at the end of the document:
“Finally, a recent correlation of backscatter observed with Pactor-II on 17-Nov-2003 to the SuperDARN derived auroral convection currents suggests that the ion clouds causing communications capable backscatter originate within the auroral ovals. On this date, there was a geomagnetic disturbance that allowed some of the auroral convection currents to escape equatorwards after there was a sudden shift in the geomagnetic field. When the geomagnetic field momentarily decreases, Faraday’s Law predicts a radial electric field that in turn induces an impulse driving some of the auroral charge equatorwards. Interestingly, combining this finding to the recent confirmation of synchronized conjugate auroras22 further explains the etiology of other interesting communications phenomenon including transequatorial spread-F (TE) discovered in 19471 emphasizing the usefulness of this propagation research.”
73,
Guru