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Was wondering about the possibility of creating a magnetic field in milliseconds or less? I know it's possible based on certain labs achieving 60-100 Tesla and more. But what about creating a 2 - 5 Tesla magnetic field in milliseconds? How much power will be required? How will the electromagnet be designed?

Typically what cooling is required? This is more of a "pulse-like" electromagnet that could be used multiple times without being damaged, like a magnetizer. Where the fields are creating somewhat instantly. What properties will this electromagnet have?

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  • \$\begingroup\$ I have a colleague that did high mag field stuff in Japan, single turn coil, that somewhat disappears during the pulse. The sample was destroyed too, so you have one shot to make the measurement. How about you give us a guess as to power, energy, B-field, size, time.... (inductance, current) \$\endgroup\$
    – George Herold
    Oct 7, 2014 at 2:33
  • \$\begingroup\$ Well why not use multiple coils, for continuos nondestructive uses? \$\endgroup\$
    – Pupil
    Oct 7, 2014 at 3:39
  • \$\begingroup\$ Here's what they look like.. the copper image on the right. takeyama.issp.u-tokyo.ac.jp/indexe.html \$\endgroup\$
    – George Herold
    Oct 7, 2014 at 12:28
  • \$\begingroup\$ @Key - If you use a lot of turns (e.g. lots of coils), the inductance of the coil increases, which means you need much higher voltages to get the current rise-time you want. Eventually, you just cannot switch enough voltage fast enough. \$\endgroup\$
    – Connor Wolf
    Nov 6, 2014 at 5:24
  • \$\begingroup\$ @GeorgeHerold The antenna disappearing into a cloud of plasma seems to be an issue with EMP stuff. \$\endgroup\$
    – Spehro Pefhany
    Dec 6, 2014 at 5:25

2 Answers 2

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The magnetic field depends directly on the amount of current through the coil. To overcome the reactance (due to inductance) of the coil, use a high voltage. Follow that with a current regulator set to the value that gives you the 2-5T field. The higher the voltage used, the faster the current will rise to the desired value.

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  • \$\begingroup\$ Well, considering the high power required during a very short time, is E = P x t? How much power/energy is needed might you'd think? \$\endgroup\$
    – Pupil
    Oct 7, 2014 at 7:09
  • \$\begingroup\$ To start, you have to know how much current the coil needs. This is not simple. Amps x turns gives you magnetomotive force. To get from that to field strength you have to include the size of the field and the material it's contained in. This is going to be worth another formal question. Only after that can you start looking at current, voltage, power, ...and duration. I understand "strong", but don't know what "fast" buys you. \$\endgroup\$
    – gbarry
    Oct 7, 2014 at 16:57
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you'd want to lower the inductance of the coil (di/dt) by connecting each loop of wire in parallel, instead of using a single coil of 20 loops you'd use 10 coils of 2 loops in paralel

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