I have made this reasoning, thinking about it for a time but it's time to ask to you for comments / opinions and solider advices.
Let's take a perfect gas: we know the temperature is related to the speed of the molecules. Then take this gas at a temperature $T$ and be it inside a box thermally isolated; the box is clamped (kept still) by opportune mechanisms.
Let's now suppose that the hits between the molecules and the walls of the box be perfectly elastic, and let's now apply a gravitational field.
Then the particles are accelerated whilst moving towards a wall and decelerated whilst they move towards the opposite wall. This makes a temperature gradient to appear.
Is that reasoning valid and possible?
That is my questions. Is it possible to change the $T$ of the fas by applying external fields that accelerate the particles or the action of such fields do not interfere with $T$, but maybe they do effect some other parameters?