3-D HELIOS Tomography

The image and a 1.2 Mbyte *.avi or a 0.7 Mbyte quicktime video presentation is a view of inner heliospheric plasma density (to 1.5 times the distance of the Earth from the Sun) derived from a combination of Thomson scattering intensities from the HELIOS photometers and IPS velocity data. The data from the HELIOS photometers were obtained from March 21, 1977 to April 18, 1977 (Carrington Rotation 1653). The IPS velocities were obtained from the UCSD IPS array from February 24, 1977 to May 15, 1977 (Carrington Rotations 1652 - 54). The plasma density is normalized by the removal of a 1/r squared distance dependence. The Sun is depicted as a sphere in the center of the figure, and the Earth, a blue sphere on it's orbit around the Sun. The view is from 15 degrees above the heliographic equator.

The image is obtained from a three-dimensional tomographic reconstruction of the plasma from perspective views of it available from outward motion of the plasma and solar rotation as explained in part by Jackson et al., 1997. The intensity level observed by the photometers is a least-squares fit to a hydrodynamic model over the time period observed. Because of this limitation, only the corotating component of the heliospheric plasma density and velocity can be reconstructed from the data. Clearly seen is the three-dimensional Archimedean spiral structure of the dense heliospheric components of the solar wind during this solar minimum period when the heliospheric current sheet was nearly parallel to the equator.

There is a 1.2 Mbyte *.avi perspective view video of this data set from Earth. There is also a 2.9 Mbyte *.avi video depiction of a FIRE (Solar Probe) fly-through of this data set.