Linear Transformer Drivers

A photo of a scientist testing the linear transformer drive assembly

One of the things I always loved about physics was the aura of immense, cosmic power that surrounded the experimental tools physicists build. I think this is not really appreciated by most people simply because they don’t know the science behind the design of these tools.

  • Telescopes are enormous and placed in remote, high locations for a reason.
  • Particle accelerators are gigantic for a reason.
  • High power capacitors and steam turbines are heavily armored for a reason.
  • Nuclear piles are heavily armored for a reason.
  • Gravity wave detectors are massive for a reason.
  • Neutrino detectors are placed deep in mines for a reason.
  • Even small lasers carry warning labels for a reason.
  • Electron microscopes carry warning labels for a reason.
  • Rockets are big, scary things for a reason.
  • Even kitchen table, accoustic stuff like sonoluminesce radiates this aura of immense forces confined in tiny spaces.

The reason is that each device deals in some way with fearsomely powerful, ancient, cosmic energies. We are dealing with the foundation materials of our universe and they are awesome in their power and elegance.

So what puts me in this poetic frame of mind? Some news I read today on the Sandia National Laboratories website. Russian and American scientists collaborated to build a new type of electrical circuit system called a linear transformer driver. In principle, these devices will be capable of generating 60 megamps of current, in sustained, repeated bursts at 10 second intervals.

Now, when you read that last sentence, you probably didn’t realize how difficult that is to do so, let me give some comparisons and facts:

  • It’s not really voltage that’s dangerous. It’s current. People can touch van de graff generators, which generate enormous voltages, and laugh about it because the amount of current flow is tiny. The electrical currents are passing over your skin, not through your body and, even if they did, they are usually not high enough to do any damage.
  • It takes only about a 100 milliamperes of current passing through someone’s body to kill them.
  • A typical long distance electrical transmission line can sustain currents of up 1000 amperes. To do this requires special materials and safety precautions.
  • One of the most powerful commercial electrical traction generators in the world sustains a current of 27 kiloamperes. Again, this device was not easy to build.

Now, multiply that last bullet 2,000 times. That means that current generated by the new circuits from Sandia, if distributed efficiently, could kill more than 600 million people.

Of course that last statement is a gross oversimplification. Any electrical engineer worth her salt would tell you that there is no way to achieve that level of efficiency. But it does give us some idea of the level of power involved in these gadgets–which are, interestingly enough, referred to as “bricks.” The capacitors in these circuits can explode with the force of a grenade or stick of dynamite if not handled properly.

This goes a long way to explaining why these experimental fusion devices are so enormous, expensive, formidable and scary looking when in use.

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