Just released first images from the National Science Foundation’s Daniel K. Inouye Solar Telescope reveal unprecedented detail of the Sun’s surface and preview the world-class products to come from this preeminent 4-meter solar telescope. NSF’s Inouye Solar Telescope, near the summit of Haleakala, Maui, in Hawai‘i, will enable a new era of solar science and a leap forward in understanding the Sun and its impacts on our planet.
Activity on the sun, known as space weather, can affect systems on Earth. Magnetic eruptions on the sun can impact air travel, disrupt satellite communications and bring down power grids, causing long-lasting blackouts and disabling technologies such as GPS.
The first images from NSF’s Inouye Solar Telescope show a close-up view of the sun’s surface, which can provide important detail for scientists. The images show a pattern of turbulent “boiling” plasma that covers the entire sun. The cell-like structures -- each about the size of Texas -- are the signature of violent motions that transport heat from the inside of the sun to its surface. That hot solar plasma rises in the bright centers of “cells,” cools, then sinks below the surface in dark lanes in a process known as convection. ...
<<Granules on the photosphere of the Sun are caused by convection currents (thermal columns, Bénard cells) of plasma within the Sun's convective zone. The grainy appearance of the solar photosphere is produced by the tops of these convective cells and is called granulation.
The rising part of the granules is located in the center where the plasma is hotter. The outer edge of the granules is darker due to the cooler descending plasma. (The terms darker and cooler are strictly by comparison to the brighter, hotter plasma. Since luminosity increases with the fourth power of temperature, even a small loss of heat produces a large luminosity contrast; this "cooler", "darker" plasma is still far hotter and vastly brighter than a thermite reaction.) In addition to the visible appearance, which would be explained by convective motion, Doppler shift measurements of the light from individual granules provides evidence for the convective nature of the granules.
A typical granule has a diameter on the order of 1,500 kilometers and lasts 8 to 20 minutes before dissipating. At any one time, the Sun's surface is covered by about 4 million granules. Below the photosphere is a layer of "supergranules" up to 30,000 kilometers in diameter with lifespans of up to 24 hours.>>