Morphology of magnetic holes in the pristine solar wind

Magnetic holes (MHs) are deep depressions in the magnetic field found in the solar wind and in planetary magnetosheaths. Based on Cluster multi-point data from the pristine solar wind, we investigate the morphology of MHs exhibiting no to little rotation in the magnetic field(linear MHs). In a previous study we used timing methods to determine that the MHs were moving with the solar wind, and from that we are now able to determine the spatial scales. We investigate the morphology by comparing observations to theoretical models, starting with infinitely long solenoid model. The scale sizes are related to the orientation parallel and perpendicular to the magnetic field. Here we present the preliminary results, showing a few examples, which later will be expanded to a statistical study.