CAREER: Exploring Mysterious Whistler Mode Waves in Earth's Plasmaspheric Plumes

Trustees Of Boston University, Boston

Investigators

Abstract

This project investigates how very low frequency radio waves, known as whistler mode waves, affect the Earth's Radiation Belt dynamics. Lightning produces whistler waves, which travel along the Earth's magnetic field lines. Understanding these waves and how they are amplified is important to national security and commercial interests. Military and commercial communications utilize the same very low frequency radio wavelengths and are therefore disrupted by whistler waves. The resulting scientific results will lead to improvement of predictive space weather models. This fits directly into the goals of the National Space Weather Strategy and Action Plan, released in 2015. The project supports a female faculty member and will train and educate graduate and undergraduate students in both research and outreach activities. The proposed outreach program will target K-12 students through development of interactive in-class presentations, hands-on activities, and tours of the BU observatory and planetarium. The outreach will engage undergraduate and graduate students in both research and communicating space science to the public. Whistler mode waves in plasmaspheric plumes exhibit unexpectedly large amplitudes that suggest that waves in this region are very effective in driving energetic electron precipitation. Currently, radiation belt models do not incorporate this effect. In order to understand the role whistler waves in plasmaspheric plumes play on radiation belt dynamics, this award will combine theory, modeling, and data analysis. Quasilinear diffusion theory will be used to evaluate electron scattering due to wave-particle interactions. This will be combined with modeling from a Full Diffusion code to calculate electron diffusion coefficients and a 3D diffusion code to simulate radiation belt electron dynamics. Analysis of observations from multiple spacecraft, including the Van Allen Probes, THEMIS, POES/MetOp, and GPS, will establish density, wave, and particle properties associated with the generation of whistler waves in plasmaspheric plumes. The data will be compared to the developed model to answer the science questions. The study is unique in that it focuses on whistler waves generated in plumes, a region not previously investigated. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.