Thermo guns or thermo blaster is a general term for any weapon that uses heat as a target effect.
Most prominent in this list are the Terran Thermo Kinetic Units (TKU) and the standard weapon of choice for Union and especially Terran military personnel. TKU’s have a magazine with small capsules of molecular compressed Hydrogen gas. In a thermo nuclear reaction chamber the gas is superheated to temperatures exceeding 1 million degrees, accelerated to near light speed and funnelled through a narrow force field tunnel. The result is a bolt of 99 percent pure thermal energy and one percent kinetic energy. The combination of thermal energies and kinetic energies are highly destructive and able to vaporize almost any known material instantly into molecular ashes. The energies focused at the target are so intense that it takes much shield energy to deflect or absorb it.
Other Thermo Weapons include Kartanian Flamers that use a highly flammable substance that is accelerated to Trans-sonic speeds and engulfs the target in a very hot and destructive chemical fire. There is also a kinetic impact component to this weapon.
Flame Bolters (often used by Marines) use the same principle as Kartanian Flamers but instead of a chemical, uranium pellets are melted to near gaseous state and compressed to a needle fine stream. Marine Flame bolters develop over 5000 kilos of kinetic impact energy per square millimeter and only a few highly advanced materials with Neutronium components are able to withstand it.
Thermo weapons are used by many civilizations as the harnessing of fire as a destructive force has the longest weapon technological history.
One of the earliest examples of Thermo weapons is an Anuna Thermo gun found in the European region of Earth during an archeological dig. The Anuna gun uses molecular heating to superheat ferrous particles and channel it through a magnetic field. (picture shown is the two component weapon Belt harness and hand held projector)
Please note that the Terran term Firearm does not denote a weapon that uses fire as a target effect. Terran fire arms are Chemical reaction weapons using a fast oxidation process to generate explosive expanding gases to propel a projectile.