Before revision: It would have a gas or vapor core composed of UF4 with some 4He and/or 3He added to increase the electrical conductivity, the vapor core may also have tiny UF4 droplets in it.
After revision: It would have a gas or vapor core composed of UF4 with some 4He added to increase the electrical conductivity, the vapor core may also have tiny UF4 droplets in it.