Tag: Gerold Yonas

Sandia’s fusion program

On By gyonas5 Comments

When I was working at Sandia National Laboratories, my fusion research began with a concept of highly-focused, high-current electron beams. After a few years, my colleagues decided that the energy deposition of ions would be more favorable than electron beams for target coupling and implosion. This changed our approach to ion beam focusing. It also led us to propose construction of a new pulsed power machine, which we decided to call Particle Beam Fusion Accelerator or PBFA.

In addition, the researchers emphasized the use of radiation coupling, which years later would become the key to the recent fusion breakthrough at Lawrence Livermore National Laboratory’s National Ignition Facility. We thought radiation coupling would be essential to driving a spherically symmetric implosion.

In our original plan, we thought we would need an electron beam pulse of 100 trillion watts, which was 100 times more than what we had in the lab at that time. As it turned out, that tremendous increase was still not enough. My colleagues at Sandia went through many iterations struggling to get to the 100 trillion-watt level. After many experiments, many decisions and several critical government reviews, we felt convinced that the ion approach was going nowhere. In the mid 1990s, our program was on the edge of termination. 

Then a technical miracle happened. We discovered a more promising approach to creating the radiation source. We could use a multiple wire Z pinch. We redirected all of our resources to the Z pinch. In 1998, I wrote about this effort in a Scientific American article entitled “Fusion and the Z pinch.” 

To succeed with this approach, it seemed that a much higher current pulsed power machine would be needed. I proposed a new machine called X-1, which meant yet another large increase in funding. The Department of Energy was not entirely amused, but agreed to upgrade the Z machine. With the upgrade, the program continued with improved computer simulations, diagnostics and machine performance all focused on radiation-driven targets.

Recently, Steve Slutz, a Sandia scientist, and his colleagues, came up with a theoretical breakthrough. They suggested using the Z pinch to directly compress the fusion fuel embedded in a strong magnetic field. To lower the power requirement for ignition, a laser is used to achieve the pre-heat needed to start the burn. Aided by the applied magnetic field, the laser preheats the cold fuel. The next step will to achieve ignition and then high gain. We are unsure how much energy will be needed to get a successful high gain from the fusion explosion. There are several theoretical estimates, and Sandia is now considering building a next generation Z machine to deliver 10 megajoules to a fusion target.

The quest for fusion represents decades of research. In my next post, I will discuss the contributions the Russians made to fusion research. For now, I’ll conclude by pointing out how the path to scientific breakthroughs is often littered with false starts, setbacks, disappointments and then startling breakthroughs. I describe this process in my new science fiction novel, The Dragon’s C.L.A.W., which will be released May 16, 2023. Like the fusion researchers at the real national laboratories, my characters are seeking the ultimate clean, safe, unlimited energy source. Will they succeed? Preorder the first novel in this series to find out.

Fusion: fact or fiction

On By gyonas2 Comments

With the advent of the Covid lockdown in 2020, I decided to try my hand at writing science fiction, as an activity to maintain some semblance of sanity. Based on my experiences in the Pentagon, national labs, and consulting for the government, I wrote about the fictitious discovery of an unlimited, cheap, safe energy source. The result was a series of technothriller novels, called the Project Z series. The first book, The Dragon’s C.L.A.W., will be published this May.

Now, you may ask, how much of this series is based on reality? How close are scientists to creating the ultimate energy source? Recently, as my book headed to print, scientists achieved a major fusion breakthrough at Lawrence Livermore National Laboratory.  This fusion research program exists to support the nation’s nuclear weapon program, but the breakthrough made headlines because of the potential to use fusion as an alternative energy source.

On Dec 13, 2022, Secretary of Energy Jennifer M. Granholm, announced an outstanding scientific and technical achievement. Lawrence Livermore’s device, called the National Ignition Facility (NIF), had demonstrated “fusion ignition” in a laboratory for the first time. The machine had created a nuclear reaction that generated more energy than it consumed.

Construction on NIF began in 1997 and the device started operating more than 10 years ago. The machine takes energy from a giant capacitor bank, as large as an apartment building, and transforms that energy into 192 pulsed laser beams focused onto a very complex, tiny fusion capsule.  The facility is as long as three football fields and 10 stories tall, but the final energy output comes from a tiny sphere you can barely see in the palm of your hand. Does this sound like another of those government exaggerations, maybe similar to Reagan’s “Star Wars” program he announced in 1983? Indeed, achieving fusion ignition is an incredible achievement. Let’s take a look at what happen on that fateful day at NIF.

To begin with, there was an incredible amount of stored energy in the capacitors, namely two million joules in each of 192 capacitor banks, to excite the lasers. Next the laser energy entered a 1 centimeter-long cylinder through holes on the ends and heated the inner surface of the tiny cylinder. One of the first technical challenges was that the laser pulse had to be tailored to the right shape over time. The laser light had to be precisely injected into small holes on the ends of the cylinder, and the energy had to be directed and precisely absorbed in a predetermined pattern on the inner wall of the cylinder. Both of these goals were achieved. That exquisitely tailored and perfectly focused energy was absorbed and a fraction of that energy was converted into a hot ionized gas, called a radiating plasma, expanding from the heated cylindrical target’s inner wall.

Inside the cylinder sat a tiny sphere, only 2 millimeters in diameter. Using a microscopic tube, the hollow, flawless, gold-plated diamond shell had been filled with fusion fuel. When the lasers hit the cylinder creating the hot ionized gas, radiation flowed around the sphere and heated its outer surface. This made the outer wall of the sphere explode, causing a violent implosion. A small fraction of that implosion energy compressed to heat a tiny, high density, high-temperature spot at the center of the fuel. This triggers the fusion reaction. The energy released by the fusion reaction heated a fraction of the surrounding compressed fusion fuel releasing more energy.

This was the miraculous achievement of creating a burning fusion fuel using NIF. The compression and heating of the fuel was not the really significant result, the true breakthrough was creating a small hot spot that ignited adjacent cold material. Hot spot ignition is the event that may open the way to the future. There were many tradeoffs of nonlinear variables that had to be adjusted after years of very complex experiments and calculations. And repeating the achievement is still yet to come.

Frankly, before NIF was approved by congress, I had my doubts that such a complex process based on hot spot ignition would ever work, and my skepticism did not please my friends on the NIF team. It is still very hard for me to comprehend the entirety of what happened. The sustained investment of so much money and many years of total dedication in the face of repeated failures is remarkable. The complexity of the concept, and brilliance of the scientific and engineering team, as well as the enormous difficulty of the achievement contributed to this historic event, but it is natural to question the result.

However, based on an extensive array of diagnostic sensors backed up by modeling and simulation of the complex physics, we know it really happened. There were so many incredibly challenging engineering requirements, and so many interdependent very nonlinear physical phenomena that could only be modeled on giant computers. I was skeptical at first, and I am now totally impressed that the NIF team accomplished this remarkable result.  Although the phenomenon may be rather hard to duplicate, it happened once, and that makes all of the difference in the long and arduous journey of fusion research. It is just one more of those miracles of engineering and physics!

But what about my attempt at inventing a fictional engineering and science breakthrough in my soon to be published novel, The Dragon’s C.L.A.W.  I imagined my story and began writing it several years before this real miracle occurred. In my futuristic technical mystery novel, a low energy nuclear reaction is triggered by an intense relativistic electron beam. The beam triggers a transmutation of the target material into rare earth elements, and the energy output in the form of an electromagnetic pulse is thousands of times greater than the input. No question. This is pure fiction physics, but it draws on some real research I conducted during my career. In 1972 I initiated a fusion program at Sandia National Labs, even applied for and was awarded a patent on an e-beam fusion reactor concept with construction of what I called the Electron Beam Fusion Accelerator. I’ll discuss my fusion research journey in my next post.

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Fiction may be the answer

On By gyonas10 Comments

In 1985, the magazine “Science Digest” featured a debate between me and Hans Bethe, the 1967 Nobel Prize winner in physics and my former Cornell University undergraduate quantum mechanics physics professor. The question was whether President Reagan’s Strategic Defense Initiative, SDI, could be effective against nuclear tipped Soviet missiles. Bethe’s answer was a definite, “No.”

Bethe’s most persuasive argument was, “The entire system could never be tested under circumstances that were remotely realistic.” He did not wish to tackle the psychology of deterrence. He focused on the technical issues instead.

The United States was already living with the concept of mutually assured destruction, which I knew could not be tested either. I argued it was too soon to discuss the effectiveness of any hypothetical defense system. I believed a research program was justified and would be needed in order to influence the perception of a new and safer approach to strategic stability.

There was one area of technology development that concerned me––the requirement that the split-second events in a war would have to be managed by computer software. Back then I was basically Reagan’s Ray Gun Guy, and I did not know anything about testing software. Today, it looks like Bethe was right about the importance of testing. But there’s still something he missed.

Here’s where I think Bethe went astray: testing is all about technology, but deterrence is far more complicated. The vital issues in creating a credible deterrent are not just technology, but economics, social issues, political arrangements and psychology. I learned over the years that such problems really have no final solution, and continuing to pursue the answer often leads to alternating periods of hopeful optimism and depressing pessimism… and sometimes, but not always, real progress. My published opinion was that the outcome of the SDI program would “depend not only on the technology itself, but also on the extent to which the Soviet Union either agrees to mutual defense agreements and offense limitations…no definitive predictions of the outcome can be made.”

My feelings were ambivalent. I struggled to communicate the complexity of the issue to my scientific and political colleagues. I found it even more difficult to explain the questions surrounding SDI to the news media. But one person got it. He was a cartoonist.

In the 1980s, Berkeley Breathed, the cartoonist behind the series Bloom County, created a cartoon about me, the Chief Scientist of Reagan’s SDI, aka Star Wars program. He depicted me as a chubby penguin named Opus, who claimed that enormous sums of money would be needed to develop a “space defense gizmo.” When Opus learned that the unlimited money was not forthcoming, he screamed, “Physicists need Porsches too,” and then mused that maybe “the days of wines and roses are over.” Breathed understood the reality of my job.

I had been challenged with helping to put together a $25 billion, five-year plan for a research program to accomplish Reagan’s goal of “rendering nuclear weapons obsolete.” After the plan was finished and delivered to the Secretary of Defense, I wrote that even if the research was wildly successful, any workable missile defense would have to go along with a comprehensive arms control treaty that greatly reduced our own offensive capabilities as well as the threat. In spite of my published doubts, the following year I was asked by the newly chosen program’s manager, General James Abrahamson, to be his deputy and chief scientist. We brought together a distinguished advisory group including Edward Teller, the “father of the H bomb”, Bernard Schriever, retired four star general and the father of our nation’s first ballistic missiles that responded to the Soviet threat posed by Sputnik in 1957, Simon Ramo, the father of the engineering behind that first ballistic missile technology, Fred Seitz, former head of the National Academy of Sciences, and me.

During my two years in the Pentagon, I was faced not only with many serious detractors, but also with many incidents that could have been the source of high anxiety. I realized the contradictions, irony and exaggeration in the program were inescapable. I managed to approach the many stressful moments with humor that I often expressed in satirical memos and comments that were not always appreciated by my boss. But when dealing with complicated issues, there are no simple solutions. The best you can do is hang on to your sense of humor and keep trying to help other people understand your point of view.

As a cartoonist, Breathed understands that. His fictionalized depiction of the Star Wars dilemma summed up the situation succinctly. Reflecting on his cartoons years later, I wondered if perhaps Breathed had the answer to explaining the ambivalence that I faced during my time in the SDI program. In fact, the contradictory issues related to nuclear deterrence are something all scientists working in national defense face.

So, taking my inspiration from Breathed’s penguin, I have decided to try my hand at writing fiction. This spring, I will launch the first in a series of novels about the complex interaction between science and politics. Stay tuned for more information in future posts.

Beware of the swarm

On By gyonas6 Comments

Three years ago, I speculated in my blog that fairly low-tech unmanned aircraft, UAVs, or drones could defeat very expensive missile systems after a giant Saudi oil facility was attacked with high precision causing enough damage to reduce the global oil supply. Even though there was a missile defense system in place, the attack came from a swarm of small low-flying drones and cruise missiles that defeated the existing missile defense system.

I called for an increased emphasis on defense against this type of attack, and since then, there have been many worldwide new programs focused on developing this kind of threat as well as new defense systems. The recent Russian attacks on Ukraine’s infrastructure and the Ukraine attacks against Russian air bases appear to be a demonstration of what I expected, namely a fundamental change in offense and defense.

I pointed out in my post that swarms of such weapons to surprise and exhaust even the most competent defenses could mark a radical change in warfighting. I wrote that “drones could target critical parts of the exposed grid, disperse biological agents, target crowds at sports events, or even parking lots of shopping centers.” Unfortunately, my worst fears have come to pass with the Russians targeting the cities and critical infrastructure of Ukraine. Now Ukraine has struck back, and the nastiness is only going to be even nastier with more attacks from both sides. The balloon has gone up. But wait there’s more. The latest Ukraine innovation is drone killer boats backed up by flying drones to find and strike targets at sea. So the air, sea, and space application of killer drones is going to be the new way of war. But where there are new weapons, there are certain to be new counter-weapons.

With the development of fiber laser weapons with a power level of tens to hundreds of kilowatts, a realistic defense against drone swarms is possible if the tracking, pointing, and fire control system works reliably, and if the power supply is of an ample duration, and if enough of such defense system could become an affordable deployment … and of course, the weather cooperates. Boeing has created “an anti-drone death ray truck” that may defeat the ifs, but there are a lot of ifs and as usual, the offense is already a step ahead of the defense.

What about those new all-weather high-power microwave weapons such as the Ratheon Phaser to attack the controls and brains of the drones so that they become dumb rocks instead of brilliant pebbles?  High-power microwave weapons are being developed by many countries and they will be important.  This will be a story of brains versus beams, and the details will be written as the old game of offense versus defense is repeated again and again. In any case, there is no question that the game has begun and when new technology is created, people will find a way to apply that technology to warfighting.

An eventual development could be the proliferation of low-cost killer drones, and they could become the weapon of choice for ground forces, law enforcement, and maybe terrorists or even your neighborhood crazy guys who already are using weapons developed for the military. It is likely that such killer drones will initially be under the control of an operator, but quite possibly in a few years, they will be employed using artificial intelligence to search out and target predetermined targets when they are recognized by the smart sensor on the killer drones.

Survival of soldiers and military surface systems is possible if they can move, hide, defend, and shoot back, but there is not going to be a so-called “last move” in this contest of energy weapons versus drones. There may have to be an eventual change in the tactics of all surface warfare. It could be just too dangerous for high-value targets to try to survive above ground.  Maybe survival would be achieved by deploying in tunnels and caves. But what about drone swarms used by terrorists against civilian targets?  A logical step would be to ban such weapons, but we have not done this with assault rifles. Instead, children are trained to respond to an active shooter in their schools. I wonder if children will have to return to “duck and cover” when sensors detect a killer drone swarm approaching their playground?