I am a theoretical plasma physicist at the University of Oxford working on the problem of getting Magnetic Confinement Fusion going.
The challenge is this: how do you keep a boiling turbulent 10 million °C mass of hydrogen caged long enough to generate some energy? (Don't worry about safety... if anything goes wrong it just cools down and goes "phut"... not very dramatic!)
When, on occasion, I emerge blinking into the world, I play the French Horn in the Oxford Philharmonic, write novels (none published yet) and reminisce about the fun I had in the Cambridge University Rock and Roll Acrobatic Club.
Fusion is a way of producing energy by colliding two isotopes of hydrogen (Deuterium and Tritium) to make Helium and a neutron (pictured).
This produces such a large amount of energy that burning just sixteen grams a second could generate 1GW of power.
Fusion produces no carbon dioxide and negligible amounts of radioactive waste and is an ideal source of energy for the future.
The challenge of getting fusion to work is the challenge of keeping the fuel hot enough for the reactions to happen.