Semeter Space

Joshua Semeter

Associate Professor of Electrical and Computer Engineering

Boston University

8 Saint Mary’s Street

Boston, MA 02215

(617) 358-3498

Dr. Semeter’s research concerns interactions between the Earth’s ionized outer atmosphere (the ionosphere) and the space environment.   One manifestation is the aurora-borealis, produced by the release of electromagnetic energy stored in the distant magnetosphere.   The ionosphere is electrically conducting, and so it absorbs, refracts, and modulates radio waves.  Understanding these effects is essential for the design and operation of global navigation (GPS) and communication systems.  Electric currents flowing in the ionosphere also affects terrestrial technologies, such as power grids and pipelines, via induction.  Ionospheres are inherent to all stellar-planetary systems, and their connection with the absorption of ionizing radiation suggests a fundamental connection with the evolution of habitable environments in the universe.

Activities in Dr. Semeter’s lab include the development of optical and magnetic sensor technologies, radar experiment design and signal processing (with focus on incoherent scatter radar), and the application of tomographic and other inversion techniques to the analysis of distributed, multi-mode measurements of the space environment.


Dr. Semeter began his career as a control systems engineer at Pratt and Whitney Aircraft.   He received his PhD in Electrical and Computer Engineering from Boston University in 1997, working in collaboration with the interdisciplinary BU Center for Space Physics.  For his dissertation he developed and deployed a network of imaging spectrometers along a 500-km baseline to study spatial structure in the ionospheric airglow via tomography.   From 1997 to 1999 he was as a postdoctoral fellow at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, where he focused on synthesizing ground- and space-based measurements of auroral phenomena.   During this appointment he invented a four-channel multi-spectral imaging system for imaging the aurora simultaneously in space, time, and wavelength.  From 1999 to 2004 he was a Senior Research Engineer at SRI International, where he carried out an experimental program using the NSF-sponsored incoherent scatter radar facilities.  In 2004 he joined the faculty of Boston University, where he currently serves as an Associate Professor of Electrical and Computer Engineering.

Dr. Semeter received two outstanding paper awards from the American Geophysical Union as a graduate student, and was selected to give the 2000 CEDAR Prize Lecture based on his dissertation work. In 2004 he was awarded the SRI Presidential Achievement Award for Contributions to Geospace Science. He received an NSF Early Career Development (CAREER) award as a junior faculty member.   Dr. Semeter has served as Associate Editor for the Journal of Geophysical Research, and as Director or Associate Director of the BU Center for Space Physics since 2005.  He served on the National Academy of Sciences panel charged with developing the 2013-2022 Decadal Strategy for Solar and Space Physics.  Dr. Semeter has also been recognized for his contributions as an educator, receiving the Faculty Teaching Award from the Boston University College of Engineering in 2009. 

Selected Publications

(complete list)

Semeter, J., Coherence in auroral fine structure, in Auroral Phenomenology and Magnetospheric Processes: Earth and other Planets, Geophysical Monograph Series 197, 2012.

Zettergren, M. and J. Semeter, Ionospheric plasma transport and loss in auroral downward current regions, J. Geophys. Res. 117, A06306, doi:10.1029/2012JA017637, 2012.

Dahlgren, H., G.W. Perry, J. Semeter, J.-P. St.-Maurice, K. Hosokawa, M.J. Nicolls, M. Greffen, K. Shiokawa, J.M. Holmes and C.J. Heinselman, Space-time variability of polar cap patches: Direct evidence for internal plasma structuring, J. Geophys. Res. 117, A09312, doi:10.1029/2012JA017961, 2012.

Akbari, H., J. Semeter, H. Dahlgren, M. Diaz, M. Zettergren, A. Stromme, M. J. Nicolls, and C. Heinselman, Anomalous ISR echoes preceding auroral breakup: Evidence for strong Langmuir turbulence, Geophys. Res. Lett., 39, L03102, doi: 10.1029/2011GL050288, 2012.

Butler, T.W., J. Semeter, C.J. Heinselman, and M.J. Nicolls, Imaging F-region drifts using monostatic phased-array incoherent scatter radar, Rad. Sci., doi:10.1029/2010RS004364, 2010.