Heat the core of an object or a specific point inside the object?

[physior]

hello!

is it possible to heat the core of an object or a specific point inside the object?

or are there specific objects we can do that?

obviously after heating a specific point inside the object, the rest of the object will conductively heat up too, but I wonder if there is a way to transfer thermal energy to a specific point under the surface of an object

thanks

 

[mfb]

If your core has a different material, it can be possible. Find some electromagnetic waves that pass the outer parts but get absorbed in the core.
For a homogeneous material, you can put the focus at the right spot - you still heat up everything, but the focus point gets hotter than everything else.

A more exotic way: high-energetic charged particles in matter have an interesting property - they lose most of their energy within a narrow region at the end of their flight path. If you can tolerate radiation damage and the price, you can use a particle accelerator.

Depending on the applications, there might be more practical ways. Maybe you can place a heating device close to the point you want to heat?

 

[Danger]

I wonder if you might use something like two different focused ultrasonic beams that undergo constructive wave interference at the specific point?

 

[nasu]

Yes, it is possible and is is done. See HIFU - High Intensity Focused Ultrasound.
For example, here:
http://en.wikipedia.org/wiki/High-intensity_focused_ultrasound

But it's not interference. It's the focusing of the beams at the specific points and the simple addition of the ultrasound powers at that point. In any other "point" along the beams there is only the energy of one beam. At the point of interest the energies all add up and "burn" the tumor or other unwanted tissue.

 

[LURCH]

Similar techniques are used in lithotripsy (with focussing sound waves), and Laser engraving in those clear blocks (using interferometry).