NJIT Physicist Wins NSF CAREER Award to Explore Explosive Solar Connection

Satoshi Inoue, assistant professor of physics and member of the Center for Solar-Terrestrial Research (CSTR) at NJIT, is investigating a mysterious connection between two of space’s most powerful explosions as part of a new CAREER award from the National Science Foundation.

Inoue joins a select group of researchers by earning the CAREER award — one of the NSF’s most prestigious awards designed to support early-career researchers and their development as faculty-mentors. 

As part of his project, Inoue is exploring the complex dynamics that give rise to solar flares — the largest explosions known in our solar system, capable of causing GPS disruptions on Earth and anomalies on orbiting spacecraft.  These explosions involve an intense release of free magnetic energy triggered when magnetic field lines along the Sun’s surface twist, break and reconnect. 

While researchers continue seeking ways to better predict when solar flares will occur, Inoue is looking for fresh insights into the space weather environment of the Sun by investigating the connection between solar flares and another explosive event, coronal mass ejections (CMEs). 

“CMEs are a major driving source of volatile space weather that is often associated with solar flares,” said Inoue. “Identifying the relationship and physical differences between solar flares and CMEs is a key aim of this project that could improve accuracy of future space weather forecasts, as well as our basic understanding of plasma science.”

CMEs are a phenomenon in which billions of tons of plasma are violently ejected from the Sun’s outer atmosphere, or solar corona — sometimes bursting into interplanetary space at speeds of more than 3,000 km/s. As these ejections approach Earth’s magnetosphere, they can create disruptions such as geomagnetic storms, which can disrupt electrical grids and long-distance communication lines.

Inoue says that many CMEs immediately follow solar flare eruptions in an almost domino-like fashion. However, not all do, making them a riddle for space weather researchers trying to forecast them. 

“The relationship between the solar flares and CMEs is not quite clear yet,” said Inoue. “More recently, we’ve learned that magnetic field activity powering solar flare eruptions is also very important to how CMEs are generated, particularly from the volatile region in the corona called the magnetic flux rope, where looping magnetic field lines bundle and twist up.”

Inoue is turning to state-of-the-art simulation tools to get a better picture of this region and how it becomes unstable, sparking these eruptive events.

His lab is developing and applying state-of-the-art magnetohydrodynamic simulations of the Sun’s magnetic environment during the initiation of solar flare eruptions, using observational data taken by NASA’s Solar Dynamics Observatory and NJIT-CSTR’s Big Bear Solar Observatory.  

“By taking into account the observed magnetic field this way, we can conduct the simulation in a realistic magnetic environment,” noted Inoue.

Inoue says the model simulations will incorporate a “nested grid” approach capable of mapping the solar corona’s magnetic field in fine layers as it evolves in time, offering high-resolution visualizations of the complex dynamics triggering these related solar eruptions. 

“We plan to numerically reproduce activity throughout the solar flare onset to the birth of CMEs through these simulations, and ultimately overcome a persistent problem in this field of research, which is a gap in scale between solar flares and CMEs,” said Inoue. “We hope our work eventually leads to a much clearer look at the interconnected physics at play between these two powerful explosions from our Sun.”

The CAREER-funded project will also serve to develop and teach a new data-based, graduate-level numerical simulation course and a summer school for modeling astrophysical fluids. Funding from the award includes a total of $842,846, running from February 2022 to 2027.