Adiabatische Teilchenbahnen in räumlich stark veränderlichen Feldern

Abstract

The adiabatic invariance properties for charged particles moving in an electro-magnetic field are studied for the case where the field consists of a constant homogeneous magnetic field and a small scale oscillatory electro-magnetic field varying slowly with time. The small scale part is one-dimensional and is present only during a finite (but reasonably long) time. It turns out that the adiabatic invariance of the magnetic moment as known for wavelengths larger than or of the order of the gyro-radius also applies for short wavelengths. The invariance becomes even better as the scale tends to zero. An invariance result previously obtained byKrall andRosenbluth ⁷ for a particular wave form with small amplitude follows by proper specialization. Some physical aspects of the results are discussed.