Magnetic energy is changed by reconnection of magnetic lines into current and thermal energy. This process plays a crucial role
in fusion plasmas and expresses itself there as saw tooth oscillations or disruptions.
Reconnection is also a typical process in astrophysical environments like the magnetosphere of the earth, the solar corona, and in particular the
magnetic interstellar medium. The generation of magnetic fields on galactic length scales by a dynamo is a much discussed scenario.
Here the role of the magnetic reconnection is to a large extent still open with regard to this problem of structure formation.
A fascinating aspect of magnetic reconnection is the enormous range of relevant spatial scales involved in this form of
structure formation. For example in a fusion experiment the dynamics on the macro scale (some meters) are affected by the
instabilities and turbulence on the scale of the electron penetration depth (~ 0,05 cm). A detailed overview of the area of the magnetic
reconnection is given in the monographi by Biskamp .
The magnetic field structure in the halo of galaxies is suitable under different (aforementioned above) aspects as diagnostics of the
contribution of reconnection processes for a dynamo. Therefore further investigations of the radio synchrotron polarization
are to be accomplished for magnetic field measurments in galaxies, in order to increase the so far quite small number of observations.
This is necessary, in order to characterize a "typical" case, independent of possible peculiarities of individual objects. New observations e.g. with the Very Large Array are requested in addition to the analysis of archive data, which were
not evaluated with respect to the polarization information.
The Ω-effect of the dynamo theory depends on the internal kinetics of a galaxy. The rotation curves are however
(from the HI λ21cm line observations) insufficiently known in the central regions because of resolution effects.
Therefore they have to be determined in the optical or better within the near-infrared range.
These observations are to be finally interpreted by model calculations of simple dynamos. For this, co-operation with
other groups as the MPIfR Bonn or the University of Krakau is intended.