6600vamp@ucsbuxa.ucsb.edu (Le Vampire) (02/21/91)
From: 6600vamp@ucsbuxa.ucsb.edu (Le Vampire) The press as well as many of us laymen has the tendency to throw around the words 'nuclear weapons' and 'atomic weapons' rather interchangeably. Is there a difference between nuclear and atomic weapons? Also, is a neutron bomb an atomic/nuclear weapon. From what I understand it is merely a stripped down H-bomb. Thanks for the help.
john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) (02/23/91)
From: john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) In article <1991Feb21.030902.12162@cbnews.att.com> 6600vamp@ucsbuxa.ucsb.edu (Le Vampire) writes: > > The press as well as many of us laymen has the tendency to >throw around the words 'nuclear weapons' and 'atomic weapons' >rather interchangeably. Is there a difference between nuclear >and atomic weapons? Also, is a neutron bomb an atomic/nuclear >weapon. From what I understand it is merely a stripped down >H-bomb. Thanks for the help. > Fission is an atomic process, so a fisson weapon is an atomic weapon. Fusion is a nuclear process, so a fusion weapon is a nuclear weapon. For the purposes of the press however, I can't see it matters. Also, fusion weapons are initiated by a fission weapon, so they are in fact a hybrid. As I recall, a neutron weapon is just a normal fission or fusion device with the outer neutron reflector removed. Normal atomic/nuclear weapons have an outer layer (talking rather generally) about the nuclear component whose purpose is to reflect the escaping neutrons back into the fissionable or fusionable component. This increases the blast yield. Neutron weapons (as I understand it, please correct me if I am wrong) have this ommitted. John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA
john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) (02/27/91)
From: john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) In article <1991Feb22.232819.4666@cbnews.att.com> john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) writes: > >Fission is an atomic process, so a fisson weapon is an atomic weapon. >Fusion is a nuclear process, so a fusion weapon is a nuclear weapon. > I would like to clarify my statement above, since it is misleading the way I said this. Fission itself is a nuclear process, however 80% to 90% of the kinetic energy of the fission fragments comes from the electrostatic repulsion of the nuclei. Very little of the energy is derived from the nuclear forces. So, while fission is nuclear, the energy of the weapon is derived mostly from atomic forces and hence the term atomic bomb. Sorry for the confusion. John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA
deichman@cod.nosc.mil (Shane D. Deichman) (02/28/91)
From: deichman@cod.nosc.mil (Shane D. Deichman) In article <1991Feb27.021040.21923@cbnews.att.com> john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) writes: >Fission itself is a nuclear process, however >80% to 90% of the kinetic energy of the fission fragments comes from >the electrostatic repulsion of the nuclei. Very little of the energy >is derived from the nuclear forces. So, while fission is nuclear, the >energy of the weapon is derived mostly from atomic forces and hence the >term atomic bomb. > Are you using the term "atomic" to describe electrostatic repulsion? This seems like something of a misnomer, since "atomic" is generally applied to reactions involving the valence electrons. The energy from a fission reaction, while evidenced after the fact as the repulsion of high-Z like-electric fields, still comes from the nuclear binding energy. Fission is a weak nuclear process; the nuclei involved are at the high end of the binding energy curve, where the first derivative is small compared to lower-end processes (e.g., fusion). When you figure in energy as a function of mass, then the disparity between fission and fusion becomes all the more discernable. The term "atomic" bomb was misapplied. Some may recall an old H.G. Wells story (c. turn of the century) in which there was a "nuclear bomb" -- in actuality, this device derived it's energy from purely atomic forces (as conventional high explosives). So, misapplication of scientific terms is nothing new, even in the bomb business. -shane
roberts@stsci.EDU (Jim Roberts) (03/01/91)
From: roberts@stsci.EDU (Jim Roberts) In article <1991Feb28.052457.10592@cbnews.att.com> deichman@cod.nosc.mil (Shane D. Deichman) writes: > [a completely correct discussion] > >-shane The term "atomic bomb" was a misnomer acsribable to the poor general scientific knowledge among the "experts" of the day. The ultimate energy source of "nuclear weapons" and "atomic weapons" is the energy stored in the atomic nucleus, whatever its source. -- Jim Roberts roberts@stsci.edu scivax::roberts
john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) (03/01/91)
From: john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) In article <1991Feb28.052457.10592@cbnews.att.com> deichman@cod.nosc.mil (Shane D. Deichman) writes: > >Are you using the term "atomic" to describe electrostatic repulsion? >This seems like something of a misnomer, since "atomic" is generally >applied to reactions involving the valence electrons. > I think most physicists would make the distinction of nuclear as phenomena associated with the strong nuclear force and the internal structure and dynamics of the nucleus. Atomic is usually taken to refer to phemonena associated with the interactions of electrons and nuclei with each other and with other atoms. This includes a good deal more than just valence electrons. I would say your definition is more appropiate to a chemist who is worrying about chemical reactions which involve the valance electrons than to a physicist interested in atomic structure and dynamics where you have to account for all the constituents of the atom but where nuclear forces play no part (except to bind the nucleus together). > >The energy from a fission reaction, while evidenced after the fact as >the repulsion of high-Z like-electric fields, still comes from the >nuclear binding energy. Fission is a weak nuclear process; the nuclei >involved are at the high end of the binding energy curve, where the >first derivative is small compared to lower-end processes (e.g., fusion). >When you figure in energy as a function of mass, then the disparity >between fission and fusion becomes all the more discernable. > This question of terminology has absorbed far more time already than I think it deserves. However, let me quote from an article by Harold Schmitt (Physics Division, Oak Ridge) in the "Encyclopedia of Physics" discussing fission: ..."As the compound nucleus begins to fission, this excitation energy transforms into deformation, and a sequence of shapes such as those shown in figure 1 may ensure. At the "scission point," i.e., the point of separation, the product nuclei (often called "fission fragments" or "fission products") are free to accelerate by mutual Coulomb repulsion. It is this Coulomb potential energy, and its subsequent transformation into fragement kinetic energy, which accounts for most (80 to 90%) of the energy released in fission." So, to oversimplify, once the nuclear forces are overcome by the deformation forces, you have two nuclei left which do not interact via nuclear forces and with a very small kinetic energy. Most of the 180 MeV or so of kinetic energy of the final reaction comes from the fact that you have two like charged nuclei in very close range and hence in a very high state of electrostatic potential energy. So, when I say that the majority of the kinetic energy comes from atomic forces, I am saying nothing more than that the energy is derived from non-nuclear sources, i.e., the Coulomb repulsion of the nuclei. In any case, as far as I can tell from your paragraph above, we are saying the same thing, so we are just hashing over semantics. I am not particularly trying to defend the use of the term atomic versus nuclear, as a physicist I tend to be more interested in the nuclear processes involved in causing a nucleus to fission than I am in the origin of the kinetic energy of the fission fragments, so nuclear is both more appropiate and acceptable to me as a terminology. All I was doing in my original posting (where all this started) was to explain why some people make a distinction. > >The term "atomic" bomb was misapplied. Some may recall an old H.G. >Wells story (c. turn of the century) in which there was a "nuclear >bomb" -- in actuality, this device derived it's energy from purely >atomic forces (as conventional high explosives). So, misapplication >of scientific terms is nothing new, even in the bomb business. > I think this question of whether to call it an atomic or nuclear weapon is in effect a distinction without a difference. As a physicist, I would say the correct term is nuclear, but inside the weapons community the term atomic is often generic for fission weapons and nuclear generic for fusion weapons. Samuel Glasstone wrote in the 1962 version of "The Effects of Nuclear Weapons": "A distinction is sometimes made between atomic weapons in which the energy arises from fission, on the one hand, and hydrogen (or thermonuclear) weapons, involving fusion, on the other hand. In each case, however, the explosive energy results from nuclear reactions, so that they may both be correctly described as nuclear (or atomic) weapons." John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA
chidsey@smoke.brl.mil (Irving Chidsey) (03/05/91)
From: Irving Chidsey <chidsey@smoke.brl.mil>
In article <1991Mar1.053147.29904@cbnews.att.com> roberts@stsci.EDU (Jim Roberts) writes:
<
<The term "atomic bomb" was a misnomer acsribable to the poor general
<scientific knowledge among the "experts" of the day. The ultimate
<energy source of "nuclear weapons" and "atomic weapons" is the energy
<stored in the atomic nucleus, whatever its source.
Why not ascribe it to a sharpening of the nomenclature as the
public awareness of the field developed. Remember, when the news hit the
headlines, there were no experts, if you had heard of it, you were sworn
to secrecy. There was no-one the press could turn to for advice. The
few physicists who could talk were scrambling for information beyond what
was in the press releases. Transmutation of elements was demonstrated,
the possibility of a net energy was hypothesized, and then everyone went
to work on the war and the field dropped from sight. The 'atomic' came
from some press officer who had to call it something.
Irv
--
I do not have signature authority. I am not authorized to sign anything.
I am not authorized to commit the BRL, the DOA, the DOD, or the US Government
to anything, not even by implication. The do not tell me what their policy is.
Irving L. Chidsey <chidsey@brl.mil>jmc@DEC-Lite.Stanford.EDU (John McCarthy) (03/06/91)
From: jmc@DEC-Lite.Stanford.EDU (John McCarthy) The terms "atomic energy", "atomic bomb" and "atomic scientist" were in general use in 1945 and still are, even if "nuclear ..." might be more accurate. The official Smythe report was entitled "Atomic Energy for Military Purposes" and the magazine started by physicists at that time was called and is called "Bulletin of the Atomic Scientists".