10/01/2026
By Lynne Schaufenbil

Please join the Lowell Center for Space Science and Technology (LoCSST) for a talk by Dr. Longzhi Gan of Boston University's Department of Astronomy, titled "Nonlinear Wave-Particle Interactions and Energetic Electron Precipitation in Earth’s Magnetosphere."

  • Date: Thursday, Oct. 15
  • Time: 11 a.m.

Abstract

Energetic electron precipitation (EEP) into Earth’s upper atmosphere is an important loss process for the outer radiation belt and a key pathway coupling the magnetosphere to the upper atmosphere. Plasma waves, particularly whistler-mode chorus and lightning-generated whistlers, can scatter energetic electrons into the atmospheric loss cone and produce both intense bursty precipitation and more persistent losses. Recent observations from CubeSats such as ELFIN, balloon campaigns such as BARREL, and low-Earth-orbit satellites such as SAMPEX provide increasingly detailed measurements of these processes.

In this presentation, I will discuss how linear, quasi-linear, and nonlinear wave–particle interactions contribute to energetic electron precipitation. I will first present observation-constrained simulations of several precipitation events and show how different wave-driven processes produce distinct precipitation signatures. I will then focus on nonlinear interactions driven by intense chorus waves. In particular, anomalous nonlinear interactions, which have recently been revisited after being largely overlooked for decades, can alter the expected precipitation by trapping or bunching electrons near the loss cone. These effects challenge some assumptions used in conventional diffusive descriptions and can modify estimates of radiation-belt loss.

I will also discuss how these kinetic-scale processes can be incorporated into longer-timescale transport and precipitation models, with the broader goal of connecting resolved wave–particle physics to radiation-belt evolution and magnetosphere–atmosphere coupling.

Bio

Longzhi Gan is a Research Scientist at the Center for Space Physics at Boston University and is currently visiting Embry-Riddle Aeronautical University. He received his Ph.D. in Astronomy from Boston University, where his dissertation focused on nonlinear wave–particle interactions in Earth’s radiation belts, and subsequently continued his research in Professor Wen Li’s group. His current work focuses on nonlinear wave–particle interactions, energetic-particle precipitation, and the development of kinetic transport models that connect short-timescale particle dynamics to longer-timescale radiation-belt evolution. He was selected for a 2026 Geospace Environment Modeling (GEM) Early Career Highlight for his work on nonlinear interactions between radiation-belt electrons and whistler-mode waves.

If you are interested in attending, please email Lynne_Schaufenbil@uml.edu.