Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft

• Published in: Journal of geophysical research. Space physics 2016-05, Vol.121 (5), p.4611-4625
• Main Authors: Zhelavskaya, I. S., Spasojevic, M., Shprits, Y. Y., Kurth, W. S.
• Format: Article
• Language: English
• Subjects: Algorithms; Artificial neural networks; Automation; Density; Density distribution; Electric fields; Electron density; electron number density; Empirical analysis; Instrumentation; Magnetic fields; Magnetic resonance; Mathematical models; Missions; Neural networks; Plasma; Plasma resonance; Plasma waves; Plasmasphere; Probes; Resonance; Spacecraft; Van Allen Probes; Wave measurement
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2015JA022132

We present the Neural‐network‐based Upper hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made on board NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, fuhr, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model. Key Points Developed neural network model to infer upper hybrid resonance line from plasma wave observations Applied model to 2425 orbits of Van Allen Probes data to determine electron number density Initial analysis of electron number density database as a function of L and MLT