UAH plasma researcher explores key factors in Solar Corona heating through Alfven Waves

UAH plasma researcher explores key factors in Solar Corona heating through Alfven Waves

by Russ Nelson

Huntsville AL (SPX) Nov 15, 2024

Syed Ayaz, a researcher at The University of Alabama in Huntsville (UAH), has published a study in ‘Scientific Reports’ that builds on his pioneering research into kinetic Alfven waves (KAW) as a potential explanation for why the solar corona, the sun’s outermost atmosphere layer, is vastly hotter than the sun’s surface. This latest research deepens understanding of these electromagnetic waves and their role in solar energy distribution, essential for heliophysics.

Ayaz, a graduate research assistant at UAH’s Center for Space Plasma and Aeronomic Research (CSPAR), highlighted the focus of his new work: “In our earlier study, we examined wave-particle interactions through kinetic Alfven waves in plasmas. However, crucial aspects such as energy distribution, net particle resonance speed, and the damping length of KAWs were not previously addressed.”

Kinetic Alfven waves are oscillations in the charged particles and magnetic fields within solar plasma, originating from motions in the sun’s photosphere. The damping process occurs when charged particles absorb energy from wave electric fields, heating the plasma over distances.

“This study tackled these previously unexplored issues,” Ayaz explained. “We verified our findings using data from NASA’s Parker Solar Probe and the European Space Agency’s Solar Orbiter, which corroborated our theoretical results. This is the first investigation to study these effects in non-thermal plasma, advancing our comprehension of KAW behavior in the solar corona and solar wind.”

Significance of Group Velocity

A crucial aspect of Ayaz’s research is the “group velocity,” the rate at which wave energy moves through a medium. Understanding this velocity allows researchers to examine how KAWs transport energy across the solar corona and solar wind.

“When particles gain energy from KAWs, determining their subsequent speed – or resonance velocity – is key,” Ayaz said. “This insight helps researchers grasp how particle acceleration impacts energy flow in space plasmas. Our study derives the analytical expressions for this net resonance speed, offering a way to quantify particle acceleration.”

The research also defines the damping length of KAWs, shedding light on how far these waves can transfer energy before being damped, which is important for understanding energy transfer efficiency in space plasmas.

Breakthrough in Space Plasma Studies

Ayaz emphasized that understanding the net resonance speed of particles is critical, as it quantifies how they absorb energy from KAWs and how their motion changes in response. “We’ve provided generalized analytical expressions that present a robust framework for understanding these acceleration mechanisms in non-thermal plasmas,” he said. “This insight is applicable to both small-scale and large-scale plasma dynamics in the solar corona and solar wind.”

Dr. Gary Zank, Aerojet/Rocketdyne Chair in Space Science and CSPAR director, commended Ayaz’s work: “Syed has delved into how ions, especially protons, are heated by magnetic fluctuations at small scales. This study clarifies how KAWs convert magnetic energy into heat, a process not well understood until now.”

Ayaz’s findings pave the way for further research aimed at dissecting the complex behaviors in space plasma environments. “These derived expressions are immensely valuable for the scientific community, particularly for data simulation experts,” Ayaz said. “Incorporating these formulas into computational models will refine simulations of wave-particle interactions and improve space weather forecasts. This underlines the broad applicability of our research to theoretical and computational astrophysics.”

Research Report:Alfven waves in the solar corona: resonance velocity, damping length, and charged particles acceleration by kinetic Alfven waves