It's twenty times closer to its star than the Earth; the intensity of its starlight is hundreds of times brighter. Hot enough (1,400 K) to melt gold.

I don't understand the details, but in some sense it has to be an atmospheric heat engine between the day and night side of this planet. (Its rotation is tidally locked, so they are permanently distinct sides).

The gas is probably mostly hydrogen. Hydrogen accelerated through a thermal rocket can reach 10 km/s or more.

I guess a gas giant means there's super strong electro-magnetic field.

Possibly solar radiation?