Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!nic.csu.net!csus.edu!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!ames!pacbell.com!att!cbnews!cbnews!military From: veeneman@mot.com (Dan Veeneman) Newsgroups: sci.military Subject: Message-ID: <1990Nov20.021350.26730@cbnews.att.com> Date: 20 Nov 90 02:13:50 GMT Sender: military@cbnews.att.com (William B. Thacker) Organization: AT&T Bell Laboratories Lines: 45 Approved: military@att.att.com From: veeneman@mot.com (Dan Veeneman) > From: v064lnev@ubvmsd.cc.buffalo.edu (Zerxes Bhagalia) > Could someone please point out the distinctions between a thermonuclear > device and a plain old run-of-the-mill nuclear device. Thanks in advance 8-). The terms "atomic," "nuclear," and "thermonuclear" have been bantered around in the press and non-technical publications rather freely, lending to some confusion. The term "atomic bomb" (referred to by the designers as a "device") describes the fission process of detonation, caused by the extremely rapid decay of a heavy element, either uranium or plutonium. The delay is started by bringing the element into a sufficient density ("critical mass") that the neutron flux inside the mass will exceed the threshold for a sustained reaction. The element decay is triggered by the introduction of a neutron at the proper kinetic energy (neutrons with energy too high or too low reduce the bomb efficiency). The decay itself produces more neutrons, thus continuing the cycle. The neutron "cascade" is generally primed by a booster that provides the initial neutrons (beryllium, for example). The term "thermonuclear" describes the Teller-Ulam class of (hydrogen) bombs currently in use by world powers. (In these countries, the thermonuclear weapons *are* run-of-the-mill). To greatly simplify, picture a fission bomb surrounded by a framework of light elements (hydrogen, helium, etc, i.e. those with low atomic weights). The fission device in the center is triggered, creating a number of effects, but most importantly a small area of extreme heat and pressure. The heat and pressure force the light elements to fuse together ("fusion") and in the process release binding energy. These devices can be tweaked for increased performance by the use of matched elements and the addition of "reflectors". By the way, a similar thermonuclear process is currently operating 93 million miles away, powering the sun. The term "nuclear" is a throwaway word that specifies subatomic action, but could be either fission or fusion. Hope this helps. -- Dan veeneman@mot.com