NMC Scientists Publish in Journal of Geophysical Research

NMC Scientists Publish in Journal of Geophysical Research

Alisha Vira, a student scientist at the New Mexico Consortium, along with colleagues Brian Larsen, Ruth Skoug, and Philip Fernandes, recently published their work, Bayesian Model for HOPE Mass Spectrometers on Van Allen Probes, in the Journal of Geophysical Research.

The ion composition and time variation of space plasmas are important to understand as it sheds light on the transport dynamics of charged particles through space. By improving our understanding of charged particle dynamics, we can further our knowledge of magnetic fields in space and how the system is affected by geomagnetic activity. In this study, the scientists are working to increase our understanding of the capability of space instruments, in particular the mass spectrometers on the Van Allen Probes.

To do so, scientists must rely on modeling to predict and understand the instrument response and resolution. This study uses a Bayesian approach to predict the instrument response which incorporates prior knowledge of the instrument calibration. They present a Bayesian model for the performance of the Helium, Oxygen, Proton, and Electron (HOPE) mass spectrometers aboard the Van Allen Probes. This model uses a combination of external modeling, laboratory calibration, and expert opinion to construct the spectra and demonstrates good agreement with the on-orbit data.

This study demonstrates the importance of developing an empirical Bayesian model before building the flight instrument. The Bayesian model is used to predict the time-of-flight response and thus can be used to fine‐tune the instrument development.

Alisha Vira is currently a graduate student at Georgia Tech pursuing a degree in condensed matter physics. Her graduate work is focused on the NASA REVEALS project where she is involved with investigating 2D materials for low-power, lightweight radiation detectors.

To learn more about this project read the entire article at:

Vira, A. D., B. A. Larsen, R. M. Skoug, and P. A. Fernandes (2021), Bayesian Model for HOPE Mass Spectrometers on Van Allen Probes, Journal of Geophysical Research: Space Physics, 126, 3, doi:10.1029/2020ja028862.


Above photo of Alisha Vira, student scientist who led the effort on the project.

Article by Carrie Talus, NMC.