Lorentz Cannon Fires Lightning

[Editor’s note: This video disappeared, but it has been archived here. We’re leaving the original links as-were in case they come back up.]

The aptly named [LightingOnDemand] has created a Lorentz cannon that can fire a lightning bolt. Honestly, as you can see in the video below, it looks like something from a bad 1950s science fiction movie. The inspiration was researchers using rockets trailing thin wires to attract lightning.

How does the tiny wire carry that much juice? It doesn’t, really. The wire vaporizes into plasma, and if the pulse is fast enough, the Lorentz force hold the plasma together. The rest is non-trivial high-voltage engineering.

The original gun used a Marx bank that weighed 4,000 pounds and towered 8 feet above the ground. It looked like a Gatling gun with a laser target designator.

The original capacitors were picked up from scrap and didn’t work with a high enough voltage. Raising the voltage killed many of the capacitors. Fast-forward 30 years, and high-voltage caps are cheaper and better. The new version was able to pop 150,000 volts over a sizable gap. Perfect for destroying any hostile big-screen TVs.

Based on the scaling, they estimate that a 30-foot-high Marx tower could project plasma over a quarter of a mile away. We know you aren’t likely to try this at home, but it is a fun video to watch. And, of course, Marx generators are good for other things, too. They aren’t hard to build. We’ll stick with a ray gun.

28 thoughts on “Lorentz Cannon Fires Lightning

  1. So, that 30 kiloamps starts as 150 kV DC, and dumps the charge down that skinny little wire in a fraction of a millisecond then…. where do those coulombs go?

    The target is clearly on a big metal ground plane, which must connect back to the Marx generator. This means that 30 kiloamps is running in a huge loop 8 feet high and 25 feet long. The capacitor energy is largely going to go into that spectacular flash (which is, honestly, the goal), and a bit is going into that big magnetic field pulse. I wonder how much actually gets deposited in the target — most of the energy deposited at that location will be just going into a short arc to ground, not through the device components itself.

    Fun stuff.

  2. I have recollections of seeing photos of something very much like that lorentz cannon mounted on the outside of a metal building (4:00 in the video), that was back in the proto-internet days (1997? 1998?). Not much other information comes to mind, can’t recall seeing anything about it working either. I don’t doubt it’s the same setup and people.

    That website had other information about tesla coils, capacitor banks, pole pig transformers and other beefy dangerous electric hijinks that any nerdy teenagers would drool over (I know we sure did!). Inspired us to try to make a tesla coil, we got most of the parts together (salvaged neon sign transformer, secondary coil hand wound on a PVC pipe, toroidal topload from some lamp, etc.), but we struggled to get/make capacitors that would work, and we abandoned the project.

          1. Unfortunately I do not. Didn’t keep in touch with him after graduation, which was 2006 for me.

            The friend I was chatting with yesterday and I worked in the Ion Space Propulsion lab at Michigan Tech, and he hung around sometimes. At the time he was working on a railgun.

            Sam and proper safety precautions were not things that often went hand in hand, but I never heard of any tragedy to my knowledge.

  3. I love that he just patiently waited for 30 years, and then just kept working on it like no big deal.

    I’m actually surprised the wire detonation is not more energetic; based on the size of those caps

    1. I was into them in the early 90s . At the house I lived in we had a number of videotapes by them we’d watch, they also had a pretty big publishing company including a lot of fiction by authors like JG Ballard. They were pretty well known in the punk and industrial/neo-pagan circles. It’s good to see some of them are still doing this sort of stuff.

  4. Didn’t watch the video, but, I remember these sonding rockets with wires to attract lightning… and another project that uses lasers to ionize air in a coherent ion channel. I’m just saying it would be more sci-fi-ish to replace the wires with the lasers / ion channel to guide the initial zap and then immediately ramp it up to a megazap

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