Physicists measured the central engine that produced solar flares for the first time


The Sun is a wild place. In our skies, it is very much visible from day to day, but when you look closely, our star often riots with turbulent plasma.

One of the wildest things the sun does is to take out the colossal ends of the plasma, which make our entire Earth a massive dwarf. Although this activity is quite common, we still do not fully understand what it is.

Now, for the first time, solar physicists have measured and characterized the magnetic field of the electric current of the surface of the Garguan current sheet – which extends across the core flaring region, the central engine that powers the energy release of solar flares.

Physicist Bin Chen of the New Jersey Institute of Technology said, “It has long been suggested that the sudden release of magnetic energy through the recombination sheet is responsible for these major explosions, yet its magnetic properties There is no measurement. ”

“With this study, we finally measured the magnetic field details of a current sheet for the first time, giving us a new understanding of the central engine of the solar flares of the Sun.”

The Sun’s magnetic fields are extremely complex and convoluted. Our star is a royale, turbulent ball of incredibly hot plasma, a fluid composed of charged particles that strongly interacts with electromagnetic forces.

Because the Sun is a sphere, the equatorial surface rotates faster than the poles. This results in a solar magnetic field evolving, which, in turn, can produce very strong localized magnetic fields over the entire sun, opening the sunspots from which the flares emitted.

In these local magnetic fields, the magnetic field lines may be disturbed. In the roots of solar flares, opposing magnetic field lines connect, snap, and reconnect. In addition, powerful core sheets extend into these core solar flare regions.

We know that magnetic recombination results in relativistic motion from the release of energy and the acceleration of electrons, but how and where this happened in the structure is difficult to pin down.

Cue a massive, X8.2 solar flare that occurred on 10 September 2017. It was captured at several wavelengths by the New Jersey Institute of Technology’s expanded Owens Valley Solar Array (EOVSA), which allowed the team to study 40,000 kilometers (25,000-miles) of near-sheet expansion.

“The place where all the energy is stored and released in solar flares has so far been invisible … to play on a word of cosmology, this is the ‘Dark Energy Problem’ of the Sun, and first we have to Indirectly the finding was that the flare magnetic connection sheet was present, ”said Dale Gary, EOWSA director of the New Jersey Institute of Technology.

“EOVSA images made at multiple microwave frequencies showed that we could capture radio emission to illuminate this critical region.”

(NJIT-CTS, B. Chen, S. Yu; CFA, C. Shen; Solar Dynamics Observatory)

up: Ultraviolet observations (left) and numerical simulations of flare (right).

The team combined their multi-wavelength data with numerical simulations performed by physicists at the Harvard-Smithsonian Center for Astrophysics. Not only was the magnetic field outline consistent with the current sheet match predictions, there was a magnetic, bottle-shaped structure at the top of the flare base – 20,000 kilometers (12,500 mi) from the Sun’s surface – where electrons were getting trapped and accelerated. done.

Both sheet and magnetic regenerators seem necessary for energy release and electron acceleration. According to the team’s calculations, magnetic energy is released into the current sheet at a rate of about 10–100 billion trillion joules per second. But, unsurprisingly, this is not where particle acceleration occurs.

“The release of such a huge energy on the current sheet is mind-blowing. The strong electric field generated there can easily trigger electrons for relativistic energy, but the unexpected fact we found was that the current The electric field profile in the sheet field was not coincidental. Chen stated that with the spatial distribution of relativistic electrons, we measured.

“In other words, there must have been something else to accelerate or redirect these electrons. Our data showed a special place at the bottom of the current sheet – the magnetic bottle – important in producing or limiting relative electrons. appears to be. . ”

Although such structures have been proposed before, this is the first time they have been performed, researchers have noted. And the new measurements can now be used as a baseline for the study and analysis of future solar flares, as well as further studies in electron acceleration mechanisms.

The research has been published in Nature astronomy.

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