“This is a high-speed photo taken during the Institute’s early days. It has a temporal resolution of roughly one ten-thousandth of a second. Using today’s standards, it’s just ordinary fast photography, not high-speed photography. You can find that standard of equipment at any specialty camera store,” a director at the Institute said.
“So who was the martyr who snapped the picture?” Lin Yun asked.
The director laughed. “A mirror. The photo was taken using a reflected light system.”
The Institute had convened a small meeting with several engineers. When Lin Yun put forward our request, that we needed ultra-high-speed camera equipment, several of them grimaced.
The director said, “Our ultra-high-speed equipment is still a ways away from international levels. It’s highly unstable in actual operation.”
“Give us an idea of the numbers you require, and we’ll see what we can do,” an engineer said.
Shakily, I told them our number: “We need to take around 36 million frames per second.”
I had imagined they would shake their heads, but to my surprise they burst out laughing. The director said, “After all of that, and what you’re looking for is just an ordinary high-speed camera! Your notion of ultra-high-speed photography is stuck in the fifties. We’re up to as much as four hundred million frames per second now. The top standards at the world level are around six hundred million.”
After we’d relaxed a bit, the director led us on a tour of the Institute. He pointed to a display and said, “What does this look like to you?”
We looked at it a while, and Lin Yun said, “It looks like a slowly blooming flower. But it’s strange—the petals are glowing.”
The director said, “That’s what makes high-speed photography the gentlest of photography. It can turn the most violent of processes gentle and light. What you see is an armor-piercing shell exploding as it strikes its target.” He pointed to a bright yellow stamen in the flower, and said, “See, this ultra-high temperature, ultra-high-speed jet is piercing the armor. This was taken at a rate of around six million frames per second.”
As we neared Lab 2, the director said, “What you’ll see next ought to satisfy your high-speed photography requirements. It shoots at fifty million frames per second.”
In this photo, we seemed to be looking at a still water surface. A small, invisible stone had landed on the surface, kicking up a bubble, which fractured, sending liquid particles in all directions as waves spread out in rings on the surface….
“This is a high-energy laser striking a metal surface.”
Lin Yun asked inquisitively, “Then what can you film with a hundred million frames per second ultra-high-speed camera?”
“Those images are classified, so I can’t show them to you. But I can tell you that the cameras often record the controlled nuclear fusion process in a tokamak accelerator.”
High-speed imaging of thunderball energy release progressed quickly. Macro-electrons were passed through all ten lightning stages and were excited to very high energy states, with energy levels far higher than any ball lightning ever excited in nature, allowing their energy release process to be somewhat more noticeable. The excited thunderballs entered the target area, which had targets of various shapes and compositions: wooden cubes, plastic cones, metal balls, cardboard boxes filled with shavings, glass cylinders, and so on. They were distributed on the ground or on cement platforms of varying height. Pure white paper was laid out under each, giving the whole target area the feel of an exhibition of modern sculpture. After a thunderball entered the target area, it was slowed by a magnetic damper, so it drifted about until it discharged or went out on its own. Three high-speed cameras were set up on the edges of the target area. They were massive and structurally complicated, and unless you knew what they were, you wouldn’t think they were cameras. Since there was no way of knowing beforehand which target the thunderball’s energy would strike, we had to rely on luck to capture the target.
The test started. Since it was highly dangerous, all of the personnel exited the area. The whole test procedure was directed by remote control from an underground control room three hundred meters from the lab.
The monitor showed the superconducting battery releasing the first bubble, which contacted the first arc. The monitoring system transmitted a distorted rushing sound, but the loud crack carried across the three hundred meters from the lab. The excited ball lightning moved slowly forward under the influence of the magnetic field, passing through nine more arcs as thunder rumbled ceaselessly from the lab. Every time the ball lightning contacted an arc, its energy levels doubled. Its brightness didn’t increase correspondingly, but its colors changed: from dark red, it turned orange, then yellow, then white, bright green, sky blue, and plum, until at last a violet fireball entered the acceleration area, where it was whipped by an acceleration field into a torrent. In the next instant, it entered the target area. Like plunging into still water, it slowed down, and began to drift among the targets. We held our breath and waited. Then, after a burst of energy and a flash of light, a tremendous noise came from the lab that shook the glass cases in the underground control room. The energy release had turned a plastic cone into a small pile of black ash on white paper. But the high-speed camera operators said that the cameras had not been trained on that target, and so nothing had been recorded. Another eight thunderballs were subsequently fired off. Five of them discharged, but none of them struck the targets the cameras were trained on. The last energy release struck a cement platform supporting a target, blowing it to bits and causing an immense mess in the target area, so the experiment had to be halted until the lab, which now smelled heavily of ozone, was set up again.
Once the target area was reset, the tests continued. One macro-electron after another was fired at the target area to play a game of cat and mouse with the three high-speed cameras. The optics engineers worried about the safety of their cameras, since they were the equipment nearest to the target area, but we pressed on. It wasn’t until the eleventh discharge that we captured an image of a target being struck, a wooden cube thirty centimeters on a side. This was a wonderful example of a ball lightning discharge: the wooden cube was incinerated into ash that retained its original cubic form, only to collapse at a touch. When the ash was cleared, the paper beneath it was completely unaffected, with not even a burn mark.
The raw high-speed image footage was being loaded into the computer, since if we were to play it back at normal speed, it would be more than a thousand hours long, of which only twenty seconds would show the target being struck. By the time we had extracted those twenty seconds, it was late at night. Holding our breath and staring at the screen, we pulled back the veil on that mysterious demon.
At a normal twenty-four frames per second, the whole clip lasted twenty-two minutes. At the time of discharge, the thunderball was around 1.5 meters from the target; fortunately, both the thunderball and the target were in frame. For the first ten seconds, the thunderball’s brightness increased dramatically. We waited for the wooden cube to catch fire, but to our surprise, it lost all color and turned transparent, until it appeared only as a vague outline of a cube. When the thunderball had reached maximum brightness, the cube’s outlines had totally vanished. Then the thunderball’s brightness decreased, a process lasting five seconds, during which the position formerly occupied by the cube was completely empty! Then the outlines of the transparent cube began to take shape again, and soon it regained corporeality and color, only gray white—it was now a cube of ash. At this point, the thunderball was entirely extinguished.