How does nuclear fusion in a stars atmosphere work?

How Does Nuclear Fusion Work

There are various cycles of Thermo-nuclear reactions specific to each star as given out by their spectra (surface temperatures).

Other than that, across-the-board "fusion' is not at all a significant process anywhere in stars (very low statistical probability too builds up to a significant on-going process, though) except when a star is a Nova or Supernova where the requisite amount of ultra-high pressures get developed to crush atoms to "fuse". [why didn't you ask your astrophysicist; it would be worth our while also know it ?]

I guess I must be out of the loop...

Fusion requires extreme heat and pressure to be sustained; the atmosphere of a star (even the sun's corona) wouldn't meet either requirement to my knowledge; I've always seen fusion referenced being within the material of the star; occasionally, there are *layers* of fusion going on - at least, in the cases of very massive stars - but none (that I know of) takes place in the atmosphere of a star.

Simple terms, Gravity is trying to crush the sun to a garden size pea which which converts the hydrogen (amongst other elements) into helium which counters the gravity. The outward pressure from the fusion stops gravity from allowing the star to collapse in on itself so it keeps on going around in a big loop until all the hydrogen is used up. Which the sun starts using the helium which burns at a higher temperature causing the sun to turn into a red giant before dying. Far as I know fusion come from within not on the surface.

Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy. This makes stars hot and bright.

Nuclear fusion is an atomic reaction that fuels stars. In fusion, many nuclei (the centers of atoms) combine together to make a larger one (which is a different element). The result of this process is the release of a lot of energy (the resultant nucleus is smaller in mass than the sum of the ones that made it; the difference in mass is converted into energy by the equation E=mc2).

Stars are powered by nuclear fusion in their cores, mostly converting hydrogen into helium.

The production of new elements via nuclear reactions is called nucleosynthesis. A star's mass determines what other type of nucleosynthesis occurs in its core (or during explosive changes in its life cycle). Each of us is made from atoms that were produced in stars and went through a supernova.

Small stars: The smallest stars only convert hydrogen into helium.

Medium-sized stars (like our Sun): Late in their lives, when the hydrogen becomes depleted, stars like our Sun can convert helium into oxygen and carbon.

Massive stars (greater than five times the mass of the Sun): When their hydrogen becomes depleted, high mass stars convert helium atoms into carbon and oxygen, followed by the fusion of carbon and oxygen into neon, sodium, magnesium, sulfur and silicon. Later reactions transform these elements into calcium, iron, nickel, chromium, copper and others. When these old, large stars with depleted cores supernova, they create heavy elements (all the natural elements heavier than iron) and spew them into space, forming the basis for life.

http://3.bp.blogspot.com/_cwrSE63jF7Y/S7upNZxkcFI/...

... small amounts ... must be really really tiny small. First I've heard of it, outside of white dwarfs. Is your astrophysicist talking about coronal loops and nanoflares? How about CH stars? Yellow supergiants? Is this some sore of trick with NeNa or MgAl cycles?

It is NOT at the surface where fusion occurs. It is too cold and too little gravity.