Yes, small Fusion reactors are possible. Some friends of mine recently built a Fusor and it’s pretty awesome.
A Farnsworth-Hirsch Fusor uses a negatively charged electrode to pull Deuterium ions into the center of the device at high speed. When Deuterium ions collide, there is a small chance that they will fuse into either Helium 3, or Tritium, and release a high energy Neutron.
I have recently been working on my own fusion reactor. It uses a variant of an existing style of ion containment called a Penning Trap, but activates ions and controls their movement to guide them on self intersecting orbits. The closest device I have found so far is the MIGMA reactor invented by Bogdan Maglich more than 40 years ago.
If you are interested in Fusion, you should come down to ProVolt sometime.