Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

CLaSP Seminar Series - Dr. Doug Rowland

Date: October 19, 2017
Time: 3:30 pm - 5:00 pm
Location: SRB Auditorium, room 2246

Our guest for this week's CLaSP Seminar Series will be Dr. Doug Rowland of NASA Goddard Space Flight Center. Please join us!

Title: “The VISIONS sounding rocket missions — high resolution imaging of low altitude ion outflow”

Abstract: The Earth is, at times, the largest source of plasma in the near-Earth magnetosphere. During these intervals, typically during geomagnetic storms, O+ and H+ from the ionosphere are energized by up to five orders of magnitude as they are lifted from the topside ionosphere (0.1 eV) to achieve escape velocity (10 eV for O+) to ion conic energies observed in the magnetosphere (10 keV). Once in the magnetosphere, the O+ ions especially can have a range of strong impacts, from modifying reconnection rates to determining the stability of the magnetotail to setting wave growth rates in the inner magnetosphere. A chain of processes has been implicated in this multi-step ion acceleration process, but the relative contributions of each process are still to be determined.

The first steps in this chain set the mass flux that reaches high altitudes — the low altitude region from 400 km (near the exobase, where densities are high and where the mean free path becomes long) - 1000 km and beyond). The higher altitude steps in the chain determine the energy flux, and the maximum energy the particles can obtain. But, in order to understand how much O+ enters the magnetosphere, it is important to study the “low-altitude gate” which controls how many O+ ions can reach the higher altitudes, where they may be further accelerated.

At low altitudes, the energization processes are primarily ion heating (Joule heating, which sets the height of the exobase and the temperature of the seed population), electron heating (from precipitating electrons), and wave-particle interactions. Soft electron precipitation is particularly of interest, as it can set up an ambipolar field which can lift O+ ions, energizing them by a few tenths of an eV.

To study this chain of processes, we developed the VISIONS line of sounding rocket missions. They combine high resolution in situ measurements of the drivers of ion outflow (electromagnetic energy inputs and charged particle precipitation as well as waves) along with a remote sensing component that measures the electron precipitation characteristics over a wide area (multispectral wide-angle visible light imager) and the resulting ion acceleration (miniaturized energetic neutral atom imagers). VISIONS-1 was launched into the recovery phase of an auroral substorm from Poker Flat, AK on Feb 7, 2013 and provided the first high resolution imaging of ion acceleration produced primarily by soft electron precipitation over a volume ~1000 km in diameter. We will present the results from the VISIONS mission, with a primary focus on the ENA imaging of ion outflow, as well as a brief excursion on some interesting results from the visible light imager regarding rapid O/N2 variations in the observed volume. Finally, we will present plans for VISIONS-2, funded to launch into the geomagnetic cusp in December 2018 as part of the Grand Challenge Initiative.

Biography: Doug Rowland is a research scientist in the Space Weather Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, MD. He did his PhD at the University of Minnesota, studying the development of the inner-magnetospheric large scale electric field and its effects on ring current development. He came to NASA in 2003 as a National Research Council postdoc and has been a civil servant since 2005. While at NASA, he has focused on the physics of the coupled magnetosphere-ionosphere-thermosphere system, primarily studying coupled ion-neutral dynamics and particle acceleration mechanisms, including the mechanisms that create heavy ion outflow. He has primarily used sounding rockets to study M-I coupling and I-T dynamics, but has also developed satellite-borne sensors, including the NSF-funded Firefly Cubesat. He is currently the Mission Scientist for NASA’s ICON mission and the Deputy PI for the MEME-X Small Explorer Concept Study.

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3:30 pm - 5:00 pm
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3:00 pm - 5:00 pm
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December 13th
6:00 pm - 9:00 pm
Michigan Reception at AGU
December 14th
3:30 pm - 5:00 pm
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