I actually noticed a problem in the FOX News article about the free-electron laser. In the article, they say,
"Called the FEL -- for free-electron laser, which doesn't use a gain medium and is therefore more versatile -- it was tested in February consuming a blistering 500 kilovolts of energy, producing a supercharged electron beam that can burn through 20 feet of steel per second."The problem is that they claim the laser produces a "supercharged electron beam" which is what burns "through 20 feet of steel per second." If the reporter had researched free-electron lasers, he would have known that the laser does produce an electron beam, but the beam oscillates causing the emission of an intense beam of photons, or a laser beam. It is the intense laser beam that does the burning, and not the electron beam.
I believe this inaccurate reporting, even though it seems like a small detail, is due to the fact that the FOX reporter is most likely not a scientific journalist, and so he did not understand the science in the first place. There is another possible reason for the misreporting; the reporter might have believed that readers would not understand the science, so he simplified the science to focus on the big picture. However, scientific journalists are much rarer nowadays than previously, so the first hypothesis is likely the correct one.
I am also interested in the rail gun report seen in the FOX article. It appears the Navy does not believe the rail gun will be ready until 2025. Yet, there have been references to rail gun technologies in older video games (Metal Gear Solid, in which the big bad machine is equipped with a rail gun) and movies (Transformers 2, in which the Navy takes down a giant machine on top of a pyramid with a shot from a rail gun). Word gets around, I suppose.
Great post, Ben. You raise our interest by focusing on the news story and then correct it with your scientific knowledge.
ReplyDeleteI might suggest that you further explain the difference between the electron beam and the laser beam for us.
I posted a comment on the FOX article with the following explanation [with additions for this comment in square brackets]:
ReplyDelete"The FEL [free-electron laser] creates a high-powered beam of electrons... However, that beam is sent through an alternating magnetic field, which causes the moving electrons to change direction. The electrons end up moving left and right as they move forward. The left and right motion of the charged electrons creates photons, or light. With many electrons doing the same thing, many photons are released, and the result is a very intense beam of light --- a bright laser beam. It is the laser beam that burns through 20 feet of steel per second, not the electron beam. The electron beam would fall apart if it traveled through air to reach the steel. [This is because the electrons would hit the atoms in the air and scatter away from the rest of the electrons.] Light, on the other hand, can travel through air without much change to the overall beam [since scattering off of air is less of an issue with light]. More info about FELs can be found at Wikipedia."