| Term: | BounceMotion |
| Definition: |
The second adiabatic invariant is associatedwith periodic bounce motion of charged particles trapped between twomagnetic mirrors on a magnetic field line. The second invariant, termed J,is defined by using the integral J = m ∫ v|| * ds where m is themass of the charged particle, v|| is the particle velocity along the fieldline, and ds represents elemental arc lengths along the field line. Thesecond adiabatic invariant is conserved as long as changes in the backgroundmagnetic field occur at time scales much longer than the bounce time of thecharged particles. |