Hydrogen Bomb, Thermonuclear weapon or Fusion weapon

Hydrogen Bomb or Thermo-nuclear Weapon-

It is the weapon working on the principle of nuclear fusion. A hydrogen bomb is a second-generation nuclear weapon which is more compact and a lower mass makes it very powerful than the first-generation atomic bomb.
NOTE- The first test of a fission ("atomic") bomb released an amount of energy approximately equal to 20,000 tons of TNT (84 TJ). The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 million tons of TNT (42 PJ).
- So the Hydrogen bomb is 1000 times powerful than an atomic nuclear fission based weapon.
Modern fusion weapons consist essentially of two main components: a nuclear fission primary stage (fueled by U-235 or Pu-239) and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium(D2O) and tritium(T2O), or in modern weapons lithium deuteride(LiH). For this reason, thermonuclear weapons are often called hydrogen bombs.

A Fusion explosion is started by the nuclear fission reaction in its stage one which raises its temperature very fast up to 100million Kelvins causing it to glow with thermal X-radiations. The radiation channel filled with Polystyrene foam between the primary and secondary stage within an enclosure called radiation case which confines the X-ray energy and resists its pressure. The distance separating two stages ensure that fission fragments cannot disassemble the secondary stage of fusion.

The secondary fusion stage consisting of an outer pusher/tamper, fusion fuel filler and the central plutonium spark plug is imploded by the X-ray energy collide on its pusher. This compresses the entire secondary stage and drives up the density of the plutonium spark plug. The density of the plutonium fuel rises to such an extent that the spark plug is driven into a supercritical state, and it begins a nuclear fission chain reaction. The fission products of this chain reaction heat the highly compressed, and thus superdense, thermonuclear fuel surrounding the spark plug to around 300 million kelvins, igniting fusion reactions between fusion fuel nuclei. In modern weapons fueled by lithium deuteride(LiH), the fissioning plutonium spark plug also emits free neutrons which collide with lithium nuclei and supply the tritium component of the thermonuclear fuel.

The secondary's relatively massive tamper (which resists outward expansion as the explosion proceeds) also serves as a thermal barrier to keep the fusion fuel filler from becoming too hot, which would spoil the compression. If made of uranium(U) or plutonium(Pu), the tamper captures fast fusion neutrons and undergoes fission itself, increasing the overall explosive yield. Additionally, in most designs, the radiation case is also constructed of a fissile material that undergoes fission driven by fast thermonuclear neutrons. Such bombs are classified as three-stage weapons, and most current Teller–Ulam designs are such fission-fusion-fission weapons.

The first full- scale thermonuclear test was carried out by the United States in 1952; the concept has since been employed by most of the world's nuclear power in the design of their weapons. The design of all modern thermonuclear weapons in the United States is known as the Tellar-Ulam Configuration for its two chief contributors Edward Teller and Stanislaw Ulam, who developed it in 1951 for the United States, with certain concepts developed with the contribution of physicist John von Newmann. Similar devices were developed by the Soviet Union, United Kingdom, France, and China.