MHD Reconstruction of a Magnetic Cloud in the Solar Wind

We use for the first time the two-dimensional (2-D), magneto-hydrodynamic (MHD) reconstruction technique to examine a magnetic cloud structure in the solar wind. The MHD reconstruction technique is based upon the initial-value integration of the steady, 2-D, ideal MHD equations to generate the cross section of field and plasma of a structure seen by a spacecraft. On 15 May, 2005, a super-intense geomagnetic storm was triggered by a magnetic cloud, which was observed by the Advanced Composition Explorer (ACE) spacecraft in the solar wind at 1 AU. Here AU is the astronomical unit (similar to 1.5 x 10(8) km). A size of similar to 0.20 AU (length) x similar to 0.15 AU (width) of a left-handed magnetic flux rope structure is reconstructed for the magnetic cloud. The axial orientation of the magnetic flux rope is directed to [-0.433, 0.744, 0.509] in Geocentric Solar Magnetospheric (GSM) coordinates system. The distance of the spacecraft from the center of the flux rope is similar to 0.05 AU. The maximum axial magnetic field of the flux rope is similar to 59 nT for which the axial current density is estimated of similar to 5 pA/m(2).