- November 06, 2017
- 4:00 p.m.
- 117A Surge Building,
- Dr. Douglas Rowland, NASA Goddard Space Flight Center,
- Faculty Host: Dr. Scott England
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.
To study these phenomena, we needed a platform that could provide low cost access to space, so that we could test out new instrumentation, a slow-moving platform so we could “hover” in the region of interest, and a platform that made a vertical cut through the region of interest, rather than a rapid horizontal cut at a fixed altitude, like a satellite. Sounding rockets are the ideal vehicles for such studies.
In this talk, I’ll present some of the aspects of NASA’s sounding rocket program that make it ideal for low-cost, targeted studies, especially those that use new instrumentation techniques, to validate them for future satellite missions. I’ll discuss the VISIONS sounding rocket mission, which we launched Feb 2013 from Poker Flat, Alaska, to study ion outflow, and I’ll introduce the VISIONS-2 mission, expected to launch as part of the Grand Challenge Initiative from Ny Alesund, Svalbard, Norway, in December 2018. The talk will be designed to have something of interest for both engineering and science students, as well as researchers in the field.
Bio: 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, and has worked on 17 payloads to date, 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.