Hello! I hope that i am doing this right. This is my first post of a question. So, I've been reading about a design for a fusion reactor called a "Polywell". The Polywell, as I understand it, works by sending electron beams to the device's center which suck in protons/deuterium/tritium/etc. so that they collide with each other. Like with all proposed fusion reactors, minimizing energy loss is important. I am reading about how "magnetic mirrors" are used to contain electrons and/of protons so that they do not escape the system and take energy with them. At least this is how I've interpreted it. Is a magnetic mirror essentially a magnetic field that reflects particles that collide with it? Does it work kind of like throwing a ball against a wall, or like a cage fighter bouncing themself off the ropes? I know these analogies are not perfect, but do they capture the general concept? Also, in the future, should I ask shorter questions and/or provide less background information?