But that goal has foundered on the HPM weapon's main technical challenge: generating a pulse that is directed enough to pick out a specific target and powerful enough to have an effect when it gets there, ideally using a generator that is small and light enough for an airplane or missile to lift.
A battery-powered device can generate an HPM pulse, but producing the kind of highly concentrated power needed to destroy electronics typically requires detonating a conventional explosive inside a device that destroys itself in the act of pulsing (see 'E-blast'). Because doing this inside a piloted aircraft is risky — “a few pounds in the right place will take down anything”, notes Zimmerman — the Air Force has in recent years pursued HPM weapons designed for single-use missiles.
For example, the Counter-electronics High-power Microwave Advanced Missile Project (CHAMP) is an experimental cruise missile designed to take out electronic targets such as production sites for weapons of mass destruction. Neither the Air Force nor Boeing, its main contractor for CHAMP, will discuss technical details of the program. But the project is just a prototype; when CHAMP was flight-tested last year, it still didn't include the HPM payload.
It is possible to make a microwave generator compact enough for a missile. Engineers at Texas Tech University in Lubbock have developed an experimental explosive-based source less than 2 meters long and 16 centimeters in diameter (M. A. Elsayed et al. Rev. Sci. Instrum. 83, 024705; 2012). But lead developer Andreas Neuber points out that there are physical limits: to maximize the microwave power while keeping the system small, the engineers had to increase the internal electrical field. The result can be a catastrophic failure of the system's insulating materials that short-circuits it before the system can build up much power.
Even if the military succeeds in packaging an HPM system, there is serious doubt over how effective the pulses will be when they hit their targets. In the late 1980s, a device called Gypsy successfully took out a bank of personal computers during the Air Force's first unclassified test of a microwave weapon. But building on that success “became an incredibly difficult research project”, says Doug Beason, a physicist who was associate director for threat reduction at the Los Alamos National Laboratory in New Mexico until 2008, and wrote The E-Bomb (Da Capo, 2005), a discussion of directed-energy weapons. “You could understand how microwaves affected components of electronic circuits — transistors, capacitors, inductors and all that. But when you started putting them together in complex circuits, it became more of a stochastic process and you wouldn't always get the same results each time.”
There is similar uncertainty over how electromagnetic energy flows through enclosures such as buildings. The process is chaotic, says Edl Schamiloglu, an electrical engineer at the University of New Mexico in Albuquerque who is involved in a multi-university research initiative funded by the US defense department to improve such predictions. “When an electromagnetic ray or wave-beam enters the enclosure,” he says, “it will continue bouncing around and not repeat its trajectory.”
In short, more than 20 years after the Gypsy test, scientists still can't reliably predict the damage a weapon would do. And that is without even considering the countermeasures that an adversary might use, which could be as elementary as surrounding sensitive electronics with a Faraday cage — the equivalent of the aluminum mesh used to shield microwave ovens.
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Reply | Report Abuse | Link to thisIronic isn't it? Just last month you had a news blurb right in your own magazine about some physicists who sucessfully produced a MASER using a Laser pumping system I believe. Wasn't the article something like, "First Practical Maser (Microwave Laser) Is Built". Look it up with the search option on the term MASER. Maybe sometimes pre-conceptions can get in the way of innovation? Of course, there's a long way to go yet.
Reply | Report Abuse | Link to thisI definitely feel it would be worth having somethings like those weapons and am in favour to carry on with the research. New ideas and materials might bring solutions. I saw a picture of the first cavity magnetron, it was as big as a desk. A few months later they made them small enough to fit them into 1940 era fighter planes.
Reply | Report Abuse | Link to thisWow - the "Active Denial System" - how appropriate!
Reply | Report Abuse | Link to thisOn a clear day (with low atmospheric humidity) this technology might be considered threatening. What with global warming, will the future effectiveness of such weapons be increased or decreased?
Yes, by all means, lets fund some more of these stories - they're priceless!
Right, but a MASER generates a focused, coherent electromagnetic beam (not necessarily microwaves), whereas this article implies that we are looking for more of an area or theater capability and a globular radiative path.
Reply | Report Abuse | Link to thisI don't believe that we are talking about the same concept.
Yes, my point was (at least I intended it to be) that the military view of a MASER as a "weapons system" blinded them to any "out of the box" innovative thinking. That fact (and the fact that any military research has basically been classified for 50 years) has basically stopped any research on possible other uses and advances in MASER technology. Look at that Scientific American article I mentioned in my previous post. It appeared on 16 August 2012.
Reply | Report Abuse | Link to thisThe advances mentioned in that 16 August article are:
1. The entire apparatus sits easily on a tabletop.
2. It operates at room temperature. No extreme low temperature cooling required.
3. It produces a coherent directed beam of microwave radiation at what is still a relitivly low power...but nearly a million times higher than any other Maser before.
The difference in results, in my opinion, is that this new research was simply done to see if the idea worked, all the previous military reaserach was to make a weapon.
They simply ignored anything that didn't "look like" a weapon. That pre-conception made them blind to other possible uses of a low power Maser.
Or as the saying goes, "When all you want to do is break rocks, everything looks like a hammer to you."
Nicely put, but as I recall the correct saying (one of my favorites) is: 'To a man whose only tool is a hammer, every problem appears to be a nail'.
Reply | Report Abuse | Link to thisHowever, that one doesn't quite fit here...
If they want a tactical area weapon, what is wrong with simple microwave sources from a few microwave ovens being grouped together with 1 side unshielded and run by battery? I'm not saying it would be small or low power but it should be unpleasant.
Reply | Report Abuse | Link to thisThe FBI stole N. Tesla's papers upon his death; they've remained hidden since the 1940's. Tesla, of course, had invented a "Death Ray" useful to, perhaps, being a winning game-changer in WW-2, Korea, Vietnam, and a few other conflicts. Where are Tesla's papers today?
Reply | Report Abuse | Link to this«Despite 50 years of research on high-power microwaves, the U.S. military has yet to produce a usable weapon» I found the above news extremely encouraging. Perhaps one day we will learn to devote our intellectual and economic capital to something more rewarding (if less profitable for some) than attempting to find new ways to kill or otherwise incapacitate people....
Reply | Report Abuse | Link to thisHenri