Thermonuclear bursts

Pulsed plasmas containing hydrogen isotopes can produce bursts of alpha particles and neutrons as a consequence of nuclear reactions. The neutrons are useful for radiation-effects testing and for other materials research. A dense plasma focus filled with deuterium at low pressure has produced 10 neutrons in a single pulse (76) (see Deuterium AND TRITIUM). Intense neutron fluxes also are expected from thermonuclear fusion research devices employing either magnetic or inertial confinement. 

Figure 4 Regions of the density vs. temperature plane in which the various hydrogen-burning processes are dominant [MAT84c]. The normal CNO cycle occurs in stars slightly larger than the sun. The hot (beta-limited) CNO cycle is particularly important in supermassive stars. The rp-process is important during the thermonuclear runaways on accreting neutron stars which may be the source of X-ray bursts.

The partitioning of radioactive debris in the troposphere and stratospheric regions is determined by the total explosive yield and the height and latitude of the burst. The total yield is the sum of the fission and fusion yields of the device. The production of important fallout radionuclides is determined by the fission yield of the weapon. Smaller yield nuclear explosions are produced by fission reactions, while larger yield explosions result from boosted fission or thermonuclear fusion reactions. Of the total yield of all atmospheric tests of440 Mt, an estimated 182 Mt, or about 40% of the total, was fission yield and the remainder was fusion yield. The contributions of countries conducting atmospheric tests to the total fission yield is shown in Table 10.3. 

Keywords Supernovae, core collapse, thermonuclear explosions, gamma-ray bursts... 

The Marshall Islands test of a thermonuclear weapon could not have been more different. There was a burst of unprecedented power in that explosion, equal to 15 million tons of tnt, compared with the 22,ooo-ton equivalent in the Nagasaki bomb. And the Marshall Islands bomb detonated nearer the surface, so that large quantities of earth, sand, and water were admixed and fused with the radioactive fission products. 

Of the energy emitted from a thermonuclear air-burst, about one third is radiated in the form of light and heat rays. This intense energy is distributed over a wide area and is sufficient, in the case of a 1 megaton weapon, for example, to cause rapid photodegradation of polymers at range of more than 10 km. Fluorinated polymers are the most resistant against thermonuclear radiation [1740, 1741]. 

---