Plasma pressure distribution in the inner magnetosphere and the applicability of Dessler-Parker-Sckopke relation to storm time magnetic disturbance description Original Research Article

Dessler-Parker Sckopke relation connects the magnetic field disturbance near the center of dipole plasma trap with the total energy of particles trapped in the dipole magnetic field. It is widely used for magnetospheric ring current description. The real plasma trap has a dipole character only till 5–6 Earthʹs radii and non zero plasma pressure near its boundary. So Dessler-Parker-Sckopke relation must be re-analyzed for the case of a finite plasma trap. Such analysis shows that a new term in the relation arises. This term is determined by plasma pressure at the trap boundary. It vanishes if such pressure is equal to zero and leads to positive magnetic field disturbance near the Earth if such pressure is finite. Experimentally observed plasma pressure distribution in the inner magnetosphere during quiet and disturbed time is analyzed. It is shown that modelling of geomagnetically effective component of ring current requires the introduction of a high latitude eastward ring current. The influence of such a current on the magnetospheric magnetic field distribution and magnetopause motion is discussed.