Density Enhancements in the Solar Wind Plasma - Cluster Data Analysis

Abstract: In this study density variations in the solar wind are examined based on data from the Cluster Mission. The data are originating from the stream outside the bowshock and thus they are spanning in an interval of three to four months for each mission year up to 2006. As the data are examined, variations above the relative electron density threshold of 1.3 are archived. The variations are analyzed in terms of position, orientation, magnetic field perturbation and scale sizes. The magnetic field perturbations are exhibiting diamagnetic and paramagnetic behavior and a possible link to similar observations inside the magnetosphere is attempted through the impulsive penetration mechanism. The final conclusion of the report is that plasma density enhancements, similar to those identified from previous studies inside the magnetosphere, are also evident in the free solar wind stream close to earth.