Yes, there is, it is so warm there that Jupiter gives off more heat than it receives from the Sun. Most likely this is the energy of Jupiter, compressed at the stage of formation of a solid body.
A little more about Jupiter:
Gas giant planets don't really have a solid surface, and if I want to land on them, will I just walk through them?
Yes, they have a relatively small stone or metal core. Relatively - the mass of Jupiter's core is about 10 Earth masses.
Yes, they have a relatively small rock or metal core. Relatively, the mass of Jupiter's core is about 10 Earth masses.