Chromosphere

The chromosphere (Greek color cover) is subsequent to the photosphere layer of gas in the sun's atmosphere. It consists predominantly of hydrogen and helium, extends up to an altitude of about 2,000 kilometers above the photosphere and then goes into the solar corona.

The only total solar eclipse visible for seconds chromosphere radiates predominantly in deep red, but is otherwise completely outshone by the photosphere. Your gas density increases with the height of 10-11 from 10-15 g / cm ³. At the same time the temperature of 5800 K at the photosphere to below 4,000 K decreases until then in the upper chromosphere rises to about 10,000 K. Within a few thousand miles down the chromosphere is in a transition layer and from there on into the corona, which is heated by insufficiently understood effects to 1 to 2 million degrees.

Gas splashes in the chromosphere

Because of their very low density contributes the chromosphere to the total radiation of the sun at only insignificantly. Without visual aids, such as special filter (H -alpha filter), they can only be observed during a total solar eclipse. It then appears at the solar limb as a reddish, jagged upward structure.

Some scientists noticed at the solar eclipse 1877 in this only briefly visible narrow Farbsaum countless upward gas splashes. According to their shape they were called spicules ( spicules lat = spikes, spears ), but their nature long remained enigmatic. Very clearly then she pointed her first discoverer Angelo Secchi SJ of the Vatican Observatory. He compared the Spiculen the chromosphere with the flames of huge bushfires or a burning prairie. The chromosphere is growing " out of a uniform sub- layer [Note: the photosphere ] out and make an impression, as if constantly beat up flames ".

As was first recognized in 1950, the " flame " extremely fast, tubular flow channels along magnetic fields. They are caused by violent convection vortices under the photosphere, which transport the heat radiation from the solar interior to the outside. The skyrocketing throughout spicules have diameters up to 1,000 miles and can in a few minutes 10,000 km high range, but then fall back in on itself.

Spicules as an indication of shock waves

Although the dynamics of spicules is still unclear in detail, it is likely related to strong magnetic fields and strong shock waves. Your whole contributes to the heating of the chromosphere and the lower corona layers. The temperature of the gas is such spatter in the overlying corona at 1-2 million degrees Kelvin.

The sun researcher Otto Kiepenheuer presented in 1957 the whole ( relatively thin ) chromosphere as the spray of the surging photosphere - ocean with its ever upward flowing granulation swirls before. As the light splash of the surf much higher speeds than develop the heavy waves of the sea, the spicules splashes are much faster than the flow processes in the much denser photosphere. This diagram corresponds essentially to the now well- predictable processes at shock fronts.