Scientists Are Actually Building a Freeze Ray. The Air Force Wants It Badly.

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What could a freeze ray be? A weapon? A protective device? A fancy refrigerator? The U.S. Air Force has given almost a million dollars to fund its development. What on Earth would they use it for (or is it on Earth)? This is not a comic book or science fiction tool. It's real, and it deals with some very high tech physics but a pretty simple concept in the end.

 Freeze ray in action (news.virginia.edu)

In DC comic books, there have been two supervillains called Mr. Freeze and Captain Cold. The first appearance was Captain Cold in 1957 as a villain against The Flash. He later reappeared in 1960. His comic weapon was a pistol that fired a freezing ray. In the Batman comics, 1959 saw the origin of Mr. Zero, a scientist who used a rifle that shot a freezing beam. In 1966, the television series Batman remade the character including giving him a new name, Mr. Freeze. Two years later, he was brought back to comics with that new name. 

Comic book villains with freezing weapons

Captain Cold had to wait until 1990 to appear on television's The Flash, and then in the reboot version in 2014. Mr. Freeze was played in the 1960s Batman show by three actors, and then more famously by Arnold Schwarzenegger in the movie Batman & Robin (1997). 

TV and film versions of "chilling" villains

All characters, whether they use a rifle or pistol, fire a light blue or white ray to freeze the moisture around objects and encase them in ice blocks. The ray usually is not a smooth beam but instead is irregular around the edges, sometimes showing cold gas wafting away. Just how real is this, though, and what's the story about today's scientists wanting to build such a device?

It all centers around being able to cool electronics. They generate a lot of heat, and that can either slow down their operations or stop them entirely. In recent years, electronic devices like smartphones, tablets, and laptops have become smaller and more compact, and that leaves less space for heat to exit. What do electronics makers do now to drain off the excess heat?

Sources of heat in a smartphone (Market & Technology report, Nov., 2017)

Heat pipes and vapor chambers. These are vacuum-sealed compartments with liquid inside that heats up and spreads out across the shape of the compartment. Heat pipes (invented in 1963, used in satellites in 1965) are long and wire-like, while vapor chambers are sheets. The are placed near a heat source, where the water inside conducts the heat away. 

From micronews.com

Heat sinks. These are blocks of material in various shapes that are often in direct contact with a hot spot and drain away its heat. For example, in a personal computer, they are attached directly to fans that blow it away. A heat pipe or vapor chamber sometimes might be connected directly to the heat source, and then it distributes the unwanted heat to a heat sink block instead.

Diagram (Trenton Systems) and various designs of heat sinks (Wikipedia)

Of course, if the electronics didn't generate so much heat in the first place, these devices would not be needed. Software programs alone might regulate where the hot spots are and turn on/off various electronics as needed to adjust where heat is localized. But that's just not always possible with the demands of electrical devices nowadays. And for spacecraft in a vacuum or for high-altitude military aircraft, the air is nonexistent or too thin to draw off any heat like it can do underwater on on the ground. Spacecraft and jets are intended to use as lightweight materials as possible, so it's just not practical or efficient to carry cold liquid like a car radiator to cool things off.

We need a freeze ray!

Engineering professor Patrick Hopkins at the University of Virginia wants to help spacecraft and high-altitude jets by creating one that automatically (on demand) zaps electronic components that get hot so that they cool down. He has created a special facility called the ExSiTE Lab (Experiments and Simulations in Thermal Engineering) within the university to study these types of problems.  Graduate students below are running experiments.

From news.virginia.edu

Here's how they plan to make it work. First, you apply heat. Yes, that sounds counterintuitive, but they use something very special: plasma. According to the Plasma Science and Fusion Center at MIT, plasma is "superheated matter – so hot that the electrons are ripped away from the atoms forming an ionized gas". You find it more often than solids, liquids, or ordinary gases. Examples are in lightning, fire, stars, neon lights, and the aurora.

If it's superheated, how does it cool things down? Hopkins has created special instruments with lasers that measure temperature of surfaces the instant they are hit by plasma. A plasma beam is made by applying 1.5-2 kilovolts of electricity through a ceramic needle filled with helium. Instead of heating up, there is a moment when the temperature actually goes down before increasing. The cooling lasts for just a few microseconds (millionths of a second), but it clearly happens. Nobody else had ever been able to measure so quickly, so Hopkins repeated the work again and again with the same results. Plasma cools first, then heats up a surface.

Images from ExSiTE files

Hopkins' team used data from other applications of plasma on materials to determine the most likely reason cooling happens is that something is on the surface and evaporates, thus carrying away the heat energy from the plasma. That something is probably a super-thin layer of water or carbon monoxide. Once it is gone, the plasma energy can heat up the surface as expected. Hopkins likens this process to the heat leaving our bodies when sweat or water evaporate from our skin.

Image from okfirst.mesonet.org

So, the big challenge now is to (1) develop something to detect hot spots and (2) move a plasma jet gun around to hit it (3) with enough short bursts and (4) see how well it cools the electronics. That involves a lot of factors, but with Air Force funding, Hopkins' ExCiTE lab and his spinoff company Laser Thermal will work on that. 

In a final unique twist, let's go back to the comic book character Captain Cold. In his origin story, he thought that by using radiation from a cyclotron, he could make a weapon to stop The Flash. However, his weapon was experimental and instead created a cold ray. Cyclotrons (made originally in the 1930s) normally shoot charged particles like protons and electrons in a magnetic field, and they release radiation. Plasma found in space or around black holes emits the same type of radiation! So, maybe the story has come full circle.