Time-dependent study of magnetic fields in comets giacobini-zinner and halley

Abstract Stationary MHD models are used to analyze the data of magnetic field measurements in comets Giacobini-Zinner and Halley. The contributions of the draping, of changes in the IMF, and of turbulence are separated and extended patches of unidirectional field regions are identified. A time-dependent MHD simulation of the nonstationary flow following a sudden 90° rotation in the IMF describes properly the disrupted tail condensations observed from the earth.