Аннотация:We present Cluster observations of two different types of ion-scale (with the scale of about 300-1000 km)magnetic flux ropes in the Earth magnetotail. We show that for observed flux ropes the magnetic field By has either characteristic bell-shape profile with By in the flux rope center or a bifurcated profile with By minimum in the flux rope center. The analysis shows that the current density (of about 20-60 nA/m2) is carried by electron beams with energies of several keV and density of about 10% of the background plasma density. We develop analytical and numerical kinetic models to describe the observed magnetic flux ropes. The kinetic model describing flux ropes with the bell-shape By invokes one electron population carrying the current, while the flux ropes with the bifurcated By profile requires to assume that
the current is carried by electron beams with different temperatures. We show that the developed models are in a good agreement with observations.