Remote Sensing, Space Physics, and Planetary Physics
This is sort of a catch-all category for research that built on my Ph.D. thesis and my time as a postdoc at NASA Goddard Space Flight Center. Past work in this area (in which I am not very active at this point) includes satellite imaging of the aurora, and the electrodynamics of blowing dust on Mars and its implications for atmospheric chemistry.
We are active in several technical areas in these fields. One is remote sensing of Earth’s upper atmosphere using radio signals generated by lightning. As it turns out, lightning generates strong radio signals at frequencies that are ideal for acting as a radar for the lower edge of the ionosphere. Moreover these long wavelength signals are hard to generate with man-made transmitters. Combining measurements, electromagnetic simulations, and signal processing, we have developed techniques that enable us to observe this region of the upper atmosphere more comprehensively than has been previously possible.
We have designed and implemented satellite-to-satellite radio transmission experiments to tomographically image the properties of the ionized gas (plasma) in very large volumed of near-Earth space. We are also involved in work to understand and measure the mechanisms by which high energy electrons in Earth’s radiation belts precipitate into the upper atmosphere.Some of Our Recent Papers on Remote Sensing and Space Physics
Zhai, Y., S. A. Cummer, J. L. Green, B. W. Reinisch, M. L, Kaiser, M. J. Reiner, and K. Goetz (2011), Magnetospheric radio tomographic imaging with IMAGE and WIND
, J. Geophys. Res., v. 116, A12208. [pdf reprint
Rodger, C. J., B. R. Carson, S. A. Cummer, R. J. Gamble, M. A. Clilverd, J.-A. Sauvaud, M. Parrot, and J. C. Green (2010), Contrasting the efficiency of radiation belt losses caused by ducted and non-ducted whistler mode waves from ground-based transmitters
, J. Geophys. Res., 115, A12208, doi:10.1029/2010JA015880. [pdf reprint
Han, F. and S. A. Cummer (2010), Midlatitude daytime D region ionosphere variability measured from radio atmospherics
, J. Geophys. Res., v. 115, A10314, doi:10.1029/2010JA015715. [pdf reprint
Using optimization to design an improved acoustic lens: Han, F. and S. A. Cummer (2010), Midlatitude nighttime D region ionosphere variability on hourly to monthly timescales
, J. Geophys. Res., v. 115, A09323. [pdf reprint