According to NewScientist, NASA is developing a fusion drive that theoretically can provide 300 times the thrust of any chemical rocket engine, while only using a fraction of its fuel mass. If successful, the new engine could cut the travel time to Mars from 6 months to nearly 6 weeks.

 

NASA engineers plan to use microwaves to heat the plasma to 600 million kelvin, which would generate charged alpha particles, helium nuclei. A magnetic nozzle would then channel these particles and use them for thrust.

 

You can find the full article here.

600 million kelvin seems awfully hot for the ship to withstand even if it's relatively far away (back by the engines)

It's not too bad if it's pretty rarefied, like the gases in JET and the proposed ITER