Perfect gases and gravitational field

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.
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?