The Role of the Earth's Ionosphere in Populating the Magnetosphere and Driving its Dynamics
Jason Shuster, 25 January 2021
Professor Charles Rick Chappell began his presentation by reminding the audience of a question regarding magnetosphere-ionosphere dynamics which has been commonly asked over the past half a century: “How does the ionosphere respond to magnetospheric storms?” In this talk, Rick reverses the question asking: “How does the ionosphere cause magnetospheric storms to happen as a driver?” In his presentation he demonstrated both the presence and influence of ionospheric plasma throughout various regions of the magnetosphere, including the plasmasphere, plasma trough, polar cap, magnetotail lobes, plasma sheet, warm plasma cloak, ring current, and radiation belts. Though only initially a few eV in energy, plasma of ionospheric origin can be readily energized to 10s of keV, and at times can even become the dominant source of magnetospheric ion populations compared to ions originating from the solar wind. In concert with varying IMF orientations, the ionospheric particles serve as a major driving mechanism of magnetospheric storm and substorm phenomena. For instance, ionospheric ions influence reconnection processes occurring at the magnetosphere’s nose and within the magnetotail. Ultimately, measurement of these low-energy ion populations is needed and yet remains a challenge observationally in particular because of spacecraft potential and charging effects. Thus, cold-ion detection and instrumentation remains the target of ongoing discussion, research, and future mission concepts.
You can find a recording of Rick’s seminar on our YouTube channel and a copy of his talk here.