  The effect of negative magnetoresistance for thin superconducting wire was
considered in a simple model. These phenomena originated from competition of
two mechanism: fluctuations of the order parameter and quasiparticles charge
imbalance which accompanies each phase slip event. First process results in
conventional positive magnetoresistance while the second mechanism gives the
negative contributions. Simple analytical formula is obtained for the negative
magnetic resistance caused by both the thermodynamics (TAPS) and quantum
fluctuations. Theoretical results are compared with experimental data and
demonstrate good agreement between theory and experiment.
