Printer Friendly

Math society says no to SDI funding.

Math society says no to SDI funding

Members of the American Mathematical Society (AMS) have voted to keep the organization from participating in activities that could be interpreted as support for the Strategic Defense Initiative (SDI). They also passed a resolution expressing a strong concern about the "large proportion" of mathematics research funded by military sources.

The referendum results, tabulated and released last week, mark the first time a major professional organization has taken an official stand against SDI and military funding of basic research, says Lee D. Mosher of the City University of New York. Mosher was one of the leaders in the lengthy effort to bring these issues before the AMS membership (SN: 1/31/87, p.71). About 7,000 of the society's 21,000 members voted.

The SDI resolution, says George D. Mostow, AMS president and a mathematician at Yale University in New Haven, Conn., "reflects widespread skepticism in the mathematical community about the ability of the SDI program to achieve its stated objectives." The resolution, supported by 57 percent of those voting, specifically directs that "persons representing AMS shall make no efforts ... to mediate between agencies granting ~SDI| funds and people seeking those funds."

A second resolution, approved by 74 percent of the voters, calls for a greater effort to decrease the proportion of funding for mathematics research coming from the Department of Defense (DOD). Presently, DOD funding represents about 40 percent of the support available to mathematicians.

Neither resolution precludes individuals from pursuing their own interests. "The restrictions apply to the actions of the AMS as a society," says Mosher, "not to any individual actions."

What effect passage of the resolutions will have on the AMS and its members is not yet clear. Some, including Everett Pitcher, AMS secretary and a professor at Lehigh University in Bethlehem, Pa., say that, for the most part, AMS already has very little to do with SDI and that the society's representatives in Washington D.C., are working hard to increase funding for mathematics from all sources. "I think it will have almost no effect on the day-to-day activities of the AMS," says Pitcher.

The society, however, may lose a few members. During the lengthy debate -- mainly in the form of letters to the AMS publication NOTICES -- that preceded the referendum, several mathematicians threatened to resign from the society if the two resolutions passed. They objected to the injection of complex political issues into what they see as an inappropriate forum for discussing and resolving such questions.

The AMS is only one of three major organizations representing mathematicians. The Society for Industrial and Applied Mathematics, which has a much larger proportion of applied mathematicians in its membership, has gone in a somewhat different direction and is on record as being in favor of "continued balanced funding from multiple sources" for mathematics research. The Mathematical Association of America has not taken a position.

Kenneth M. Hoffman of the Massachusetts Institute of Technology, a member of all three societies who has played an important role in pushing for increased funding for mathematics research, says the issue of military funding has been around for a long time in the mathematics community. The fact that the resolutions didn't pass by even larger margins, he says, shows some change in the direction of acknowledging that "things aren't as simple as they sometimes appear." He contends that most AMS members had too little information about how funding decisions are actually made to vote knowledgeably. I. Peterson

Laser advance amid pros and con(fusion)s of DOE fusion path

Fusion is the process that powers the sun and stars, and it is fusion that is responsible for the fury of hydrogen bombs. For decades, scientists have hoped that with a little taming, fusion energy might also provide an essentially unlimited and relatively safe source of electricity. And so, the Department of Energy (DOE) has been sponsoring several approaches to controlling the production of fusion energy.

Last week, researchers at the University of Rochester (N.Y.) who are involved in one approach -- called direct-drive inertial confinement fusion (ICF) -- announced that they had passed an important milestone on the road to harnessing fusion power. Using a 2,000-joule laser, they uniformly compressed deuteriumtritium fuel capsules to more than 100 times the fuel's liquid density, which is 10 times better than their previous directdrive laser fusion work.

The ability to uniformly compress such capsules is an essential ingredient in triggering fusion. While actually igniting the fuel will require another 10-fold increase in compression, the Rochester work shows that researchers have overcome some crucial technical problems that had threatened to stymie their efforts. According to a committee of 10 scientists who scrutinized the data earlier this month, "the results represent a significant advance in direct-drive ICF."

However, the Rochester announcement was publicly overshadowed last week by a New York Times article quoting sources who claimed that, behind a cloak of classification, a controversy is brewing over what size laser would be needed to achieve fusion. SCIENCE NEWS has confirmed that at least one scientist believes that the useful production of fusion energy will eventually require lasers with much higher energies than what is presently planned. This theorist argues that the approaches being taken by Rochester and other laser-based programs will reach a dead end because they will be too expensive. But according to other scientists, this view is an isolated one and most of the fusion community is solidly convinced that laser and other fusion programs are indeed on track.

In fusion, two atomically light nuclei -- such as the hydrogen isotopes deuterium and tritium -- merge into a heavier, more energetically stable nucleus. In order for this to happen, the light nuclei must be pushed very close together. This requires high temperatures, which also turn the fusion fuel into a plasma. And to ensure that many reactions occur, scientists must also compress the plasma to very high densities.

With the ICF approach, researchers heat and compress the fuel by illuminating it with radiation or ion beams. The Rochester group uses ultraviolet light from the 24-beam OMEGA laser to directly strike spherical fuel pellets from all sides. In contrast, scientists working on indirect-drive systems first convert laser light into X-rays, which then compress the fuel capsule quite uniformly.

The advantage of the direct-drive approach is that it is potentially more efficient. But the U.S. ICF program has emphasized indirect drive because scientists have doubted whether direct-drive systems could compress the fusion target with sufficient uniformity. (If the compression is not uniform, some regions will "balloon out," preventing researchers from obtaining the highest possible densities). Many scientists have expected that indirect drive will be the technology chosen by the DOE when, in the 1990s, it builds its full-scale Laboratory Microfusion Facility to demonstrate high-gain fusion, in which more energy comes out than is put in.

In a March 1986 review of ICF programs, however, a National Academy of Sciences committee concluded that if the Rochester group could demonstrate high uniformity by compressing a target 100 to 200 times its liquid density, "it would be necessary to take the potential of direct driver very seriously."

Using special lenses called "phase plates" to smooth out the intensity profiles of the OMEGA beams, the Rochester researchers reached this goal and reported a density of two to four times that of lead -- the highest fusion fuel density ever measured directly. Scientists working on indirect-drive ICF with 20,000 joules of laser energy at Lawrence Livermore National Laboratory in Livermore, Calif., have achieved comparable densities, although these were inferred from other kinds of measurements.

Rochester's results show that the direct-drive approach is very much in the running, says Robert L. McCrory, director of the university's Laboratory for Laser Energetics. "Although we receive far less funding, the results we're achieving are comparable to much larger and better funded programs," he says.

McCrory says the OMEGA system's yield -- or the percentage of theoretically possible nuclear reactions that actually occur in the fuel -- is still not as high as it could be, but he expects this will improve. And while the densities and temperatures obtained fall short of those needed to ignite the fuel in a self-sustaining burn, the researchers do plan to upgrade their system to 30,000 joules which McCrory says should be enough to demonstrate ignition. Congress appropriated $2 million in fiscal year 1988 to complete half of the design and engineering studies for the $39 million upgrade. After that, an estimated 1 million joules (MJ) will be needed to produce a gain of 100.

Most scientists predict that with the indirect approach, comparable gains will be possible with about 10 MJ of energy. However, P. Leonardo Mascheroni, a physicist recently laid off the from Los Alamos (N.M.) National Laboratory due to what he says was managerial politics, contends that much bigger lasers, capable of delivering 100 MJ, will be required instead.

The disagreement stems from the analysis and interpretation of data from a classified program called Centurion-Halite, in which scientists reportedly triggered fusion reactions with radiation, primarily X-rays, released by a near-by underground explosion of a nuclear bomb. The purpose of the experiments has been to learn about the behavior of fusion targets and to glean other physical data that might then be extrapolated to the lower energy conditions of the laboratory fusion programs.

Government scientists apparently arrived at the 10 MJ figure by considering the use of an ICF capsule that has not yet been made or tested. While not specifically citing the Centurion-Halite program, Mascheroni says his 100 MJ estimate is based on existing ICF capsule technology. If he is correct, all agree, the ICF program is in trouble because the cost of developing a 100-MJ laser with the technologies now planned in the ICF effort would be astronomical.

Instead, Mascheroni says he and a colleague believe that the most suitable laser for ICF is a hydrogen-fluoride (H-F) laser, which he thinks would cost much less than the other kinds of lasers being considered. Despite a cautiously favorable review of H-F laser potential by a Los Alamos National Laboratory panel in Feb. 1987, federal support for H-F laser development has pretty much dried up.

Other scientists, however, say they have great confidence in the 10-MJ estimate, and while they belive the H-F laser has merit, they argue that it also has shortcomings and that the nation simply cannot afford to investigate all fusion avenues at once. Meanwhile, Mascheroni is arguing his case with members of Congress, in the hope that they will ask the National Academy of Sciences to reassess DOE's overall laser fusion strategy.

Photo: The 24-beam OMEGA laser system sits in a room the size of a football field.
COPYRIGHT 1988 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1988, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:American Mathematical Society
Author:Peterson, Ivars
Publication:Science News
Date:Apr 2, 1988
Previous Article:Thallium, bismuth superconductivity.
Next Article:Following pi down the decimal trail.

Related Articles
Secrecy, security and SDI; the Pentagon's Strategic Defense Initiative provokes strong campus reaction while export-control issues fade into the...
How physicists feel about SDI.
Peterson's lucid writings win math honor.
Garbage Pizza, Patchwork Quilts and Math Magic: Stories About Teachers Who Love to Teach and Children Who Love to Learn.
Educated for what?
Drama in numbers: putting a passion for mathematics on stage.
Moments in math Illustrate its impact. (Mathematics).

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters