Analysis of non-planar structures with multipoint measurements

The advent of multi-spacecraft space missions like CLUSTER provides a new challenge for maximising the information return from data taken of complex magnetic field structures in the Earth's plasma environment using a spacecraft magnetometer. Most challenging are those structures which are not amenable to single spacecraft analysis techniques such as the classical minimum variance method. Minimum variance works most effectively for determining structure when the fields form a planar structure, i.e. vary in one direction. We already know that there are many instances of geophysically important structures where our current theoretical understanding implies that the planar condition is not met. Examples include simple models of flux transfer events or field line resonance structures. The underlying principle of the minimum variance technique is based on the divergence-free nature of the field; this must remain as a constraint in any further development of analysis techniques. In order to investigate the application of multipoint techniques, we simulate measurements in various scenarios for spacecraft encounters with non-planar structures, propose approaches to pattern recognition, and determine the quality conditions on analysis methods.