24-Feb-2020 NASA News item A Year of Surprising Science From NASA's InSight Mars Mission says:
A new understanding of Mars is beginning to emerge, thanks to the first year of NASA's InSight lander mission. Findings described in a set of six papers published today reveal a planet alive with quakes, dust devils and strange magnetic pulses.
In addition, scientists are intrigued by how these signals change over time. The measurements vary by day and night; they also tend to pulse around midnight. Theories are still being formed as to what causes such changes, but one possibility is that they're related to the solar wind interacting with the Martian atmosphere.
Question: Okay that's one possibility, but what are any of the others that have been considered? Or is this actually the only known possible explanation?
Possibly helpful: Discrete Aurora at Mars: Dependence on Upstream Solar Wind Conditions