Modeling of energetic neutral atoms to study solar flares and coronal mass ejections

Photo voltaic flares and coronal mass ejections (CME) are two of probably the most energetic processes within the solar system, showering the Earth’s magnetic area with billions of tons of extremely energetic plasma fuel, doubtlessly disrupting energy grids, satellites and communications networks. Understanding the underlying particle acceleration course of concerned in giant solar energetic particle (SEP) occasions like these has been one of many central issues in heliophysics analysis.

Dr. Gang Li, a professor within the Division of House Science at The College of Alabama in Huntsville (UAH), is the primary creator of a paper in The Astrophysical Journal titled “Modeling Photo voltaic Energetic Impartial Atoms from Photo voltaic Flares and CME-driven Shocks” that demonstrates—for the primary time—how energetic neutral atoms, or ENAs, may very well be used as a brand new means to probe the acceleration course of in giant SEP occasions, in addition to to distinguish between the 2 acceleration websites: giant loops in solar flares and downstream of CME-driven shocks.

“This work is more likely to excite the [heliophysics] neighborhood to think about extra in regards to the technology and propagation of solar ENA particles,” Dr. Li says. “The paper demonstrates for the primary time that ENAs can be utilized to tell apart between CME/Flare SEP acceleration, laying down the mandatory theoretical groundwork for potential future measurement of solar ENAs.”

“Dr. Li’s work offers a groundbreaking new strategy to exploring the physics of particle acceleration within the environment of the sun remotely,” says Dr. Gary Zank, director of UAH’s Middle for House Plasma and Aeronomic Analysis and the Aerojet Rocketdyne chair of the Division of House Science.

“This expands the already substantial effort within the Division of House Science of utilizing ENAs to discover distant areas of the heliosphere, the place we make the most of ENAs created within the distant boundaries of the heliosphere and neighboring interstellar medium to discover the plasma physics of these areas.”

“The final word aim of utilizing ENAs is to acquire numerous physics parameters on the acceleration websites,” Dr. Li notes. “Scientists know that particles might be accelerated at two potential places: both solar flares or CME-driven shock. Nonetheless, which web site is extra environment friendly in accelerating particles? Which web site can speed up particles to greater energies? These are sometimes debated questions, and we have no idea the reply.”

The principle barrier to fixing these mysteries by means of experimental remark is the sun itself, as fundamental understanding of near-sun circumstances and the bodily processes concerned within the manufacturing of SEP occasions is hampered by an lack of ability to make direct measurements close to the acceleration websites.

ENAs signify a possible new technique for supplying solutions, as a result of they’re impartial particles (hydrogen atoms) which might be shaped from protons from change alternate reactions. As a result of they’re impartial, they aren’t affected by magnetic fields.

“This is essential, as a result of these impartial particles will not be affected by the solar wind MHD [magnetohydrodynamic] turbulence as they propagate from the sun to observers,” Dr. Li explains. “As compared, protons, ions and electrons, as a result of they’re charged, their propagation from the sun to the Earth is distorted by the solar wind magnetic area. ENAs subsequently carry all of the physics data of the acceleration web site. So, observing them gives a wholly new alternative to constrain the underlying particle acceleration course of.”

Additionally, the energetic atoms can reveal their secrets and techniques at a distance of 1 astronomical unit, or about 150 million kilometers from the sun, the place the flux of the ENAs are at a stage that may nonetheless be measured by a devoted ENA detector. The hunt to retrieve this information may finally result in a brand new NASA solar mission to raised perceive these particles and the way giant SEP occasions originate to impression the Earth’s magnetosphere.

“Our simulation kinds a theoretical foundation for decoding future ENA observations,” Dr. Li notes. “Such observations are probably on the radar of NASA as a future mission, for instance, the NASA SMEX mission, to dedicate to solar ENA examine. A devoted ENA mission that filters out the extra quite a few charged SEPs and goes straight after these ENA measurements can present new details about SEP acceleration close to the sun and assist remedy long-standing questions which have baffled the neighborhood.”

Actually, a brand new NASA mission on which Dr. Zank is a co-investigator, known as IMAP (Interstellar Mapping and Acceleration Probe), will in reality have ENA devices at 1 astronomical unit able to measuring ENAs created each within the distant reaches of the heliosphere and in addition originating from the sun.