Electromagnetic field representation in inhomogeneous anisotropic media

Some of the basic developments in the theory of electromagnetic field representation in terms of Hertz vectors are reviewed. A solution for the field in an inhomogeneous anisotropic medium is given in terms of the two Hertz vectors. Conditions for presentation of the field in terms of uncoupled transverse electric and transverse magnetic modes, in a general orthogonal coordinate system, are derived when the permeability and permittivity tensors have only diagonal components. These conditions are compared with some known special cases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47031/1/339_2004_Article_BF00883972.pd

Subthreshold Pion Production with Associated Multiplicity Selection in the Reaction 139La + 139La → π ± + X

We have measured the energy and angular dependence of charged-pion production, with associated multiplicity selection, in La+La collisions at 138, 183, and 246 MeV/nucleon. The pions are produced mainly in collisions with a large number of participants. The general behavior of the spectra is consistent with results at higher energies, but the yield of subthreshold pions depends much more strongly upon the target and projectile mass. The pion spectra at 246 MeV/nucleon exhibit a strong charge dependence.

Subthreshold negative pions and energetic protons produced at θcmθ_{cm} = 90° in 246 MeV/nucleon 139La+139La^{139}La+^{139}La collisions

The inclusive cross section for subthreshold negative pions and high energy protons produced at θcm = 90° has been measured for 139La + 139La at 246 MeV/nucleon. The spectrum of negative pions exhibits no bump or sharp break as has been suggested by theoretical speculation on the formation of a pionic instability in central nucleus-nucleus collisions. The measured spectra for both pions and protons are compared with results of a phase space model and an intranuclear cascade calculation