This was my first trip to California, so I was wide-eyed at the three-car garages in Beverly Hills and the sizes of the salads and the pepper grinders in the restaurants. It was, for both John Toll and me, also our first presentation at a Physical Society meeting. So we rehearsed our ten-minute talks with an audience of one in the hotel room we shared.
By the time of this trip to Los Angeles, Wheeler had secured the blessing of the lab director, Norris Bradbury, for the Princeton project, provided it was clearly an extension of the Los Alamos lab and answerable to Los Alamos, a condition perfectly acceptable to Wheeler (although the project staff would be Princeton employees).{10} Wheeler was not yet in a position to invite others to join the project, except for Toll and me. However, as early as the summer of 1950, he had raised the possibility of a Princeton H-bomb project with his friend Lyman Spitzer, the Princeton astrophysicist, and had secured Spitzer’s agreement to help. In December 1950, after an observing session at the 100-inch Mt. Wilson telescope in California, Spitzer stopped by at Los Alamos to be briefed on thermonuclear progress.{11}
Two or three months later, in February or March 1951, following a ski holiday in Aspen, Colorado, Spitzer visited Los Alamos again, this time fired up about an idea for controlled fusion power that he had formulated while skiing.{12} He was ready to propose to Wheeler that if the Princeton project became reality, it could pursue both controlled and uncontrolled thermonuclear reactions—for electric power and for bombs.
Almost from the day of its discovery, nuclear fission was recognized as a likely source of controlled power, not just a source of violent explosions. Over the years, controlled power (reactors) and uncontrolled power (bombs) were developed in parallel—although largely by different groups. Fusion followed a different path—or paths. Very early, such as at the time of Oppenheimer’s 1942 gathering in Berkeley, physicists recognized fusion’s potential for explosive energy release—a goal achieved a decade later. Controlled fusion power appeared to be a more formidable task—and so it has proved to be. Yet by 1951 there was a sense of guarded optimism that it was a goal that might be reached in a decade or so. New ideas, especially if advanced by someone of Spitzer’s stature, were worth listening to.
On the morning of Spitzer’s planned visit to the lab, some security clearance glitch delayed his admission, and he was stewing about it. So John Toll and I were dispatched to the Los Alamos Lodge to have lunch with Spitzer and calm him down. Over lunch he shared his idea with us. Take a torus (a slender doughnut), fill it with a hot (very hot) plasma of deuterium, grab the torus with two hands, and twist in opposite directions until the torus becomes a figure eight. Thread a magnetic field through the device. Then, Spitzer reasoned, the deuterium nuclei, instead of drifting in one direction and hitting a wall, would drift back and forth within the enclosure, avoiding collision with the wall long enough to permit thermonuclear “burning” to take place.
Later in the day, the security problem was resolved and Spitzer was able to unveil his idea to Wheeler—and no doubt to Teller and others. Either that very day, or perhaps soon after, Wheeler and Spitzer put their heads together and decided to make the Princeton project a double-bodied (and two-headed) enterprise, to pursue controlled and uncontrolled fusion side by side. Both aspects of fusion energy were, at the time, classified secret. Within a few years controlled fusion research began to open up (especially after the 1955 Atoms for Peace conference in Geneva), and by now is entirely unclassified. Yet in December 1951, with Matterhorn just half a year old, an official of the New York Operations Office of the Atomic Energy Commission felt compelled to write to the financial officer Roy Woodrow at Princeton reminding him that personnel in the two branches of Matterhorn were not permitted to discuss their respective work with each other.{13} This was a stricture to which we paid no attention.
Despite this agreement between Wheeler and Spitzer, as late as April 1951 memoranda among officials at Princeton were referring to “Wheeler’s project.”{14} Spitzer was, in fact, named to an oversight committee, and not replaced on that committee until May.{15}
By early March 1951 Wheeler was feeling confident enough about the reality of his Princeton project that he felt free to write to notable physicists around the country inviting their participation. Here is language from a letter he wrote to Harvard Professor Wendell Furry on April 6:{16} “I hope conditions will permit [your continued work in pure physics]. They may not. My personal guess is an appreciable chance of war by September. You undoubtedly have your own probability estimate. You may be doing some thinking about what you will do if the emergency becomes acute.” Wheeler wrote in a similar (or identical) vein to others. In his autobiography he says that he contacted 120 senior colleagues by letters, telephone calls, telegrams, and personal visits, among whom only one, Louis Henyey, an astrophysics professor at UC Berkeley, was sufficiently moved to join the project.{17} “So I turned to bright, interested younger people,” Wheeler wrote, and added, “Fortunately, the mental muscle of a theoretical physicist can reach peak performance early. In this mostly under-thirty group we had a lot of talent, enough to get the job done.”{18}
Up until May 1951, “Wheeler’s project” had no name. That is uncharacteristic of Wheeler, famous for his coinages and for his flair. The under-the-radar namelessness was resolved in a meeting among Wheeler, Spitzer, and a senior financial officer of the University, Roy Woodrow, in a Palmer Lab office on May 25.{19}, [64] (It must have been a little unusual for Woodrow to journey across campus to meet in the physics building. When I later sat in on a meeting with these three, it was in Woodrow’s office.) In capsule form, here is the conversation that apparently took place on that occasion. Woodrow: Your project needs a name. Spitzer: How about Matterhorn? That symbolizes challenge and also reflects the fact that I had an idea for a device while skiing. Wheeler: OK, Lyman, you can name the project if I get to name your device. How about Stellarator? That symbolizes harnessing the energy of the stars. Many years later, Spitzer wrote that he suggested the name “since the Matterhorn is a spectacular peak which can nevertheless be climbed with sufficient effort.”{20}
I don’t know if they shook hands. But that was that. Matterhorn B (for bomb) and Matterhorn S (for Stellarator) officially came into existence that month and existed in tandem until Matterhorn B shut down in 1953. Then, in 1958, Matterhorn S changed its name to the Princeton Plasma Physics Laboratory at the time that research on controlled fusion was released from secrecy restrictions. The Stellarator has evolved and remains an object of study, not just in Princeton but in laboratories around the world. As of this writing, the international newsletter “Stellarator News” is published regularly by Oak Ridge National Laboratory “by and for the stellarator community.”{21}
64
By chance the Greenhouse Item shot was fired at Enewetak on this same date (on the other side of the international date line—May 24 in Princeton).