Team of physicists is unearthing clues of why does the sun’s corona sizzle at one million degrees fahrenheit
The Sun’s corona, which is visible to the human eye only when it appears briefly as a fiery halo of plasma during a solar eclipse, is still a mystery to scientists who study it closely. Located 1,300 miles from the star’s surface, it is over a hundred times hotter than lower layers much closer to the fusion reactor at the Sun’s core.
A team of physicists, led by NJIT’s Gregory Fleishman, has just made a discovery on a phenomenon that might start to uncover what they term “one of the greatest challenges for solar modeling” determining the physical mechanisms that heat the upper atmosphere to 1 million degrees Fahrenheit (500,000 degrees Celsius) and higher.
There are several theories, none yet conclusive, which explain the sizzling heat of the corona: magnetic energy lines that reconnect in the upper atmosphere and release explosive energy and energy waves dumped in the corona, where they are converted to thermal energy, among others.
Energy releases in solar flares and associated forms of eruptions take place when magnetic field lines, with their powerful underlying electric currents, are twisted beyond a critical point that can be measured by the number of turns in the twist.
The largest of these eruptions cause what is known as space weather – the radiation, energetic particles and magnetic field releases from the Sun powerful enough to cause severe effects in Earth’s near environment, such as the disruption of communications, power lines and navigation systems.
It is only through recent advances in imaging capabilities that solar scientists can now take routine measurements of photospheric magnetic field vectors from which to compute the vertical component of electric currents, and, simultaneously, quantify the EUV emissions produced by heavy ions.