Seminars

Lecturer: Dr. Frank Lind (MIT)
Date: 2011-02-03 10:30
Place: Aniara

Remote Sensing of the Geospace Environment Using Software Radar Arrays

Dr. Frank Lind
MIT Haystack Observatory
USA

Abstract :
The Geospace environment of the Earth extends from the upper atmosphere and ionosphere to the boundary between the Earth's magnetic field and the solar wind. This is a region of space plasma physics and is largely invisible to the naked eye with the exception of energetic phenomena such as the Aurora. The Heliosphere which extends above this region is dominated by the influence of the Sun and solar variations play a major role in driving Geospace phenomena. At the lower boundary of Geospace the coupling to the neutral atmosphere of the Earth and terrestrial weather and processes are increasingly recognized as having a strong role in some Geospace phenomena. The different regions of Geospace are coupled by physical processes which transfer energy and momentum across many spatial scales and time spans. Persistent features such as the Aurora, radiation belts, and ubiquitous waves and tides are also punctuated by dramatic events such as geomagnetic storms which are created by the Sun. The Geospace environment is global in nature and hosts significant and wide ranging changes on timescales ranging from seconds to decades (and beyond). These changes greatly influence radio wave propagation, absorption, and scattering, and also produce significant changes in the population and structure of energetic particles surrounding the Earth. The many phenomena which interact in the Geospace environment produce a range of Space Weather effects which can be of practical importance to technological society and systems.

I will discuss radio remote sensing of the Geospace environment using software radar arrays and describe how such arrays allows us to make fundamental physical measurements of this region. Using networks of advanced software radio systems it is possible to make observations of the ionosphere with both wide spatial coverage and simultaneous high resolution in space and time. Such observations can be made using a variety of techniques such as active and passive multistatic radar imaging, satellite beacon observations of TEC and scintillation, spectral monitoring, and signal time difference of arrival. I will provide examples of the current generation of radar and radio instrumentation used to make such measurement of Geospace including incoherent scatter radars, passive radars, and ground based radio arrays. Examples of how these instruments enable the detection, visualization, and detailed investigation of the physics of the Geospace environment will be highlighted. I will also discuss the next generation of instrumentation which has been enabled by advances in radio array technology and current efforts to implement such systems.


Bio :
Dr. Frank D. Lind is a Research Engineer with MIT Haystack Observatory where he has worked for more than a decade to design, implement, and operate radio science instrumentation. He is one of the principal investigators for the National Science Foundation's Millstone Hill Facility which is part of the Upper Atmosphere Facilities program. In this role he acts as the lead engineer for the Facility whose major instrument is the Millstone Hill UHF radar system. This high power large aperture radar system is used to make detailed physical measurements of the Geospace environment and has been a key instrument used in many NSF, NASA, and DoD supported investigations. His research focuses on the development of radio science instrumentation, Software Radar techniques, space plasma physics, and distributed radio array technology and applications. Dr. Lind studied at the University of Washington where he received a Bachelor of Science degree in Physics and a Bachelor of Science degree in Computer Science in 1994. He then joined the UW Geophysics Program and pursued studies leading to the Doctor of Philosophy in Geophysics in 1999. His work there focused on Passive Radar observations of the Aurora Borealis. He is currently the chair of USNC URSI Commission for Ionospheric Radio and Propagation (United States National Committee of the International Union of Radio Science ; Commission G), a member of the American Geophysical Union (AGU), and a member of the IEEE.

Created 2011-01-19 14:40:09 by Mats Holmström
Last changed 2011-01-19 14:40:09 by Mats Holmström