Nanoflares heat up the Sun's atmosphere

Sun physicists at NASA have confirmed that small and sudden bursts of heat and energy, called nanoflare, make the temperature of thin and translucent gases in the Sun's atmosphere reach millions of degrees. .

'Why is the sun's halo so horribly hot?' James Klimchuk, a physicist who embodied the Goddard Space Center's Solar Physics Laboratory at Greenbelt, Md., Asked.

The mystery of why the temperature in the Sun's aura, the outer atmosphere, can reach several million degrees K - much hotter than the temperature near the Sun's surface - has hurt scientists in many decade. New observations made with devices on Japan's Hinode satellite revealed the cause of nanoflare.

Nanoflare are small and sudden bursts of heat and energy. 'They appear with small lines that come together to form an electric field tube called a corona coil,' Klimchuk said. The aura roll is the basic component of a thin and translucent gas layer called the aura of the Sun.

Temperature map shows the active area AR10923. It is observed close to the center of the solar disk. Blue areas indicate plasma close to 10 million degrees K. (Photo: Reale, et al. (2009))

Previous scientists said that continuous heating and regularity is the explanation for the heat of millions of degrees of aura. This model shows that the aura rolls with a certain length and temperature with a specific density. However, observations show that corona rolls have a much higher density than the predicted continuous heating hypothesis. Newer models based on nanoflares may explain the observed thickness, but there is no evidence of the existence of nanoflares to date.

Observations from NASA-funded X-ray Telescope (XRT) and Ultraviolet Imaging Spectrometer (EIS) on Hinode have revealed that superheated plasma is ubiquitous in the Sun's active regions. . XRT measures plasma at 10 million degrees K, and EIS measures plasma at 5 million degrees K. 'These temperatures can only be generated by instantaneous energy bursts, ' Klimchuck, who presented the findings in meeting of the International Astronomical Association on August 6 in Rio de Janeiro, Brazil, said.

'Aura roll is a collection of streams heated by storms of nanoflares'.

Heating aura is a dynamic process. The brightness of X-rays and ultraviolet rays is highly dependent and the density of the aura is very high . Where there is low density, the brightness is also low, where the high density, the brightness will be high. Bright aura at about 1 million degrees K.

Two active areas appear as bright areas on the Sun image, taken with X-ray Telescope on Hinode spacecraft. (Photo: NASA)

Klimchuk and colleagues built a theoretical model to explain how plasma grows inside corona tubes and what makes the temperature so high.'We simulate a heat explosion and observe the aura response,' Klimchuk said. 'Then we make predictions about the amount of release from plasma at different temperatures'.

Klimchuk estimates that when a nanoflare suddenly releases its energy, plasma in low-temperature and low-density lines quickly becomes very hot - about 10 million degrees K. However, the density is still low, so Brightness is also low. Heat flows from the very hot upper part to the bottom of the corona roll, where the temperature is not very high. This process heats the dense plasma at the base of the corona coil, and because the density at the base is very high, the temperature only reaches about 1 million degrees K. This concentrated plasma extends upwards of the heat currents. Therefore, the aura roll is a collection of translucent lines of 5-10 million degrees K and bright lines of 1 million degrees K.

Klimchuk said: 'What we see is a 1-million-plasma plasma that receives energy from the flow from the super-hot plasma. This is the first time we have seen a 10 million degree plasma, which can only be generated by nanoflares 'energy bursts.'

Hinode's observations and the scientists' analysis claim that nanoflares appear on the Sun and that they are the explanation for the sun's halo temperature. These observations also determine the activity of nanoflare in the Sun's active region.

Nanoflares are responsible for changes in the X-ray and ultraviolet radiation that occur when an active region develops. X-rays and ultraviolet rays are absorbed by the Earth's upper atmosphere. The changes in the upper atmosphere can affect the orbits of satellites and the remnants of space by slowing them down, an effect called 'pulling'. Recognizing important changes in orbit to be able to timely make adjustments to avoid collisions in space. X-rays and ultraviolet rays also affect the signaling capability of radio waves and thus adversely affect communication and orientation systems. Discovered that nanoflares play a particularly important role in the solar aura heating process that has opened up new paths for understanding the impact of the Sun on the Earth.