Ion dynamics examined as comet 67P awakens from dormancy

Ion dynamics examined as comet 67P awakens from dormancy
by Robert Schreiber
Berlin, Germany (SPX) Nov 14, 2024

A recent doctoral thesis at the Swedish Institute of Space Physics (IRF) and Umea University sheds light on how the interaction between comet 67P/Churyumov-Gerasimenko and the solar wind evolves as the comet moves closer to the Sun. Research conducted by Anja Moslinger delves into the intricate motion of ions during this transition phase.

As a comet approaches the Sun, its interaction with the solar wind undergoes significant changes. While the basic mechanisms of this interaction far from and close to the Sun are fairly well-understood, the transitional stage has been less explored. Moslinger's work aims to bridge this gap by analyzing the behavior of ions within the comet's environment during this period.

"My analysis focused on the motion of individual ions to better understand how their collective behavior influences the structure of the comet's magnetosphere. When solar wind ions encounter the comet's atmosphere, they sometimes spiral in a turbulent manner, akin to leaves swirling in an autumn breeze. This ion behavior impacts how energy transfers from the solar wind to the cometary environment and how the solar wind decelerates during this critical phase," explained Anja Moslinger, a PhD candidate at IRF and Umea University.

The study of how solar wind particles slow down near obstacles like comets is a core question in space physics, especially in understanding initial deceleration. Comets serve as dynamic natural laboratories for investigating plasma interaction processes, as their distance to the Sun - and consequently their plasma environment - varies continually.

Moslinger's thesis utilized data from ESA's Rosetta mission to comet 67P/Churyumov-Gerasimenko, alongside simulations conducted with the Amitis numerical model.

Hailing from near Linz, Austria, Moslinger first engaged with comet research in 2020 during her master's project on designing a particle instrument for the Comet Interceptor mission at IRF in Kiruna. She will publicly defend her thesis titled "Physics at sub-ion-gyroradius scales near low-activity comets" at IRF's auditorium in Kiruna, Sweden, on Friday, November 15, at 09:00. The event will feature Professor Jan Egedal from the University of Wisconsin-Madison, U.S., as the faculty opponent.

Research Report:Physics at sub-ion-gyroradius scales near low-activity comets