Seriously how have I only seen one person running this?
Basics of the build is to get the biotic field and damaging biotic field as your first 2 powers (order is personal preference) and proritize larger field radius as your first big item. From there pump up ability power and get the longer field duration item. And then by round 3 you can run in and poison their team like a scuffed version of Ram ult on cooldown
It’s not just the field damage that’s good though, with all that ability power the field becomes a fairly strong source of tanking for yourself and helix rocket becomes a beast as well.
It’s flexible late game as well. You could buy the other two powers for field, but they aren’t necessary. You can max out AP and get upgrades to make field apply slowing or antiheal, or you can invest in mobility or tankiness so you can get in more safely, or you can get some rocket upgrades