# What are the largest thermal gradients achievable in a lab environment?

I am looking for a system capable of creating a gradient of $100\, \mathrm{K}/\mathrm{\mu \textrm{m}}$ on a $30\, \mathrm{\mu}\textrm{m}$ spacing of a system mounted on a Si-N membrane. My so-called nanoheater is not up to the task.

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Ahh... I was hoping this was a vague informal question. Having recently toured a toroidal fusion reactor, I can tell you where to find a $100K/\mu m$+ temperature gradient! – NeuroFuzzy Jun 21 '13 at 22:16

Laser ablation in metals achieves temperatures on the order of 100000K while the skin depth is O(nanometers). I think this adheres to the letter of your question, if not quit the text below. :-)

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I think that we need to know more about your system. Very large gradients are possible over very short times and distances: you just heat the system up a lot locally with e.g. a laser. If large thermal gradients are to exist over large areas and long times, you need some way to get rid of the heat that is conducted across / down the gradient. This will put reasonably severe limits on the time and "sideways" dimensions of the region over which there is a large thermal gradient, as a fraction of the average absolute temperature at which the sample is held.

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