This was done by the Syracuse University Lava Project where they have an artificial volcano that heats up basalt to its melting point so that they can study lava in a relatively-contained environment. Here's an article about it, although it's unfortunately light on details with the furnace's actual principle of operation:

http://arstechnica.com/science/2015/05/hot-lava-flows-in-a-par king-lot-in-upstate-ny/