Please help me understand. Attached is a pic of some quick calculations My solenoids self inductance is 0.145mH. The coil is 117 grams of copper. I calculated with 300 amps on the picture but I only put 170A through it the other day. I had it hooked up for 2 seconds touching it at the same time, it got luke warm just from the current running through P=I^2R but then I unhooked it and as soon as I disconnected the coil interestingly it went from luke warm to insanely hot from the magnetic field collapsing and cycling through the coil. According to the math I did in the picture the energy from the magnetic field should've been way under 6.5 Joules which wouldn't raise the temperature much for 117 grams of copper according to its specific heat capacity. But it felt like it went from 35C to 90 plus C. How do I explain this because the math doesn't explain it here.