Month: May 2023

Five researchers supported by NASA’s Living With a Star Program will join the 2023-2024 class of NASA’s Jack Eddy Postdoctoral Fellowship.

The early career PhDs, selected by the University Corporation for Atmospheric Research (UCAR)’s Cooperative Program for the Advancement of Earth System Science (CPAESS), will research interdisciplinary projects contributing to the field of heliophysics at a host institution for the next two years.

The Jack Eddy Postdoctoral Fellowship was founded in 2009 in honor of pioneering solar researcher John A. “Jack” Eddy. The program matches the fellows with experienced scientists at the host institutions to train the next generation of Sun-Earth researchers.

2023 NASA Jack Eddy Postdoctoral Fellowship Awardees

Peijin Zhang
Host: Dr. Bin Chen of New Jersey Institute of Technology, Newark, NJ
PhD Institution: University of Science and Technology of China (USTC)
Proposal: Radio Imaging Spectroscopy for CMEs and CME-driven Shocks

Charlotte Waterfall
Host: Dr. Georgia deNolfo of NASA’s Goddard Space Flight Center
PhD Institution: University of Manchester
Proposal: Bad News Travels Fast: Energetic Particle Transport in the Heliosphere

Robert Jarolim
Host: Dr. Matthias Rempel at National Center for Atmospheric Research | High Altitude Observatory
PhD Institution: University of Graz
Proposal: Physics-informed Neural Networks for the Simulation of Solar Magnetic Fields

Devojyoti Kansabanik
Host: Dr. Angelos Vourlidas at The Johns Hopkins University Applied Physics Laboratory
PhD Institution: National Centre for Radio Astrophysics, Tata Institute of Fundamental Research
Proposal: Remote Sensing of CME-entrained Magnetic Fields

Mei-Yun Lin
Host: Dr. Andrew R. Poppe at the University of California, Berkeley
PhD Institution: University of Illinois, Urbana-Champaign
Proposal: From Ionosphere or Moon? A Comprehensive Study of Metallic Ions in the Magnetosphere

By Abbey Interrante
NASA’s Goddard Space Flight Center, Greenbelt, Md. 

As Earth spins around the Sun, our planet’s slight tilt creates seasons. Now, research from two NASA space missions has found how the same tilt also influences seasonal differences in space weather – conditions in space produced by the Sun’s activity.

Space weather events produce the beautiful glow of the northern and southern lights, but, if intense enough, they can also endanger spacecraft and astronauts, disrupt radio communications, and even cause large electrical blackouts. Since space weather is created by particles and energy sent from the Sun, it varies with the Sun’s 11-year cycle of activity – the solar cycle. But space weather also varies on shorter timescales, such as seasonally and daily.

The new results, published in the journal Nature Communications, found that the seasonal differences are caused by a phenomenon known as the Kelvin-Helmholtz instability. This instability forms curling waves at the boundary between two regions – such as different layers of the atmosphere or between air and water – flowing at different speeds. These waves sometimes occur in Earth’s atmosphere, resulting in unique cloud formations that look like a series of crashing ocean waves. In space, these waves are composed of charged particles that are energized and pushed toward Earth, resulting in enhanced space weather effects.

The new findings confirm that Kelvin-Helmholtz waves are more commonly produced during the spring and fall equinoxes. During the equinoxes, Earth is not tilted toward or away from the Sun. As a result, the orientation of the Sun’s and Earth’s magnetic fields is ideal for forming Kelvin-Helmholtz waves. When Earth’s magnetic field is tilted at extremes toward or away from the Sun – such as during the summer and winter solstices – few Kelvin-Helmholtz waves are created.

“We have discovered that Kelvin-Helmholtz waves in the space around Earth are seasonal, which explains an important factor in the seasonal variation of space weather,” said the lead author on the new study, Shiva Kavosi, a researcher at Embry–Riddle Aeronautical University in Daytona Beach, Florida. “These waves are ubiquitous and can be found roughly 20 percent of the time around Earth, but after monitoring over an entire solar cycle, we now know there are more chances observing them during certain times of the year.”

To make the discovery, scientists used 11 years of data from NASA’s Time History of Events and Macroscale Interactions during Substorms, or THEMIS, mission, as well as four years of data from the Magnetospheric Multiscale, or MMS, mission. “The unique orbits and long period of observations by THEMIS made this discovery – which was first theorized in the 1970s – possible,” Kavosi said.

By better understanding how Kelvin-Helmholtz waves form due to Earth’s seasonal tilt, researchers can better forecast its effects and plan accordingly to ensure spacecraft and astronaut safety. “Additionally, space weather forecasters can now add this component to their models for better forecasting,” Kavosi said.

By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.