The 3-D Shape of the HCS

Three-dimensional sketch of the heliospheric current sheet. The current sheet is shown lying near the solar equator with spiraled outward-pointing fields lying above it and inward-pointing fields lying below it. The average position of the current sheet is tilted relative to the solar equator, and the current sheet also contains folds or flutes. When the sun rotates, an observer near the ecliptic will alternately lie above and below the current sheet and will see a changing sector pattern. [From Smith et al., 1978.]

This sketch is a computer-generated perspective plot of the heliospheric current sheet configuration expected from a flat, inclined sheet near the sun, which is convected outward by a uniform velocity solar wind. The inclination of the current sheet assumed in this diagram is 15 degrees. Positive fields will be observed above the current sheet (during every other phase of the solar cycle) and negative fields below. A stationary observer near the solar equatorial plane will see two oppositely directed sectors per solar rotation. It can be seen that both sectors will adopt the standard Parker spiral configuration. [From Jokipii and Thomas, 1981.]

Artist's rendition of the heliospheric current sheet for a slightly inclined circular neutral line on a solar source surface. This drawing demonstrates the three-dimensional structure of the current sheet as it would evolve in a constant solar wind flow resulting in the usual two sector pattern. In practice, a four-sector per solar rotation pattern (and sometimes even higher) is quite usual implying that the 3-D shape of the HCS is even more complex than shown on this picture.

References

Jokipii, J. R., and B. T. Thomas, Effects of drift on the transport of cosmic rays, 5, Modulation by a wavy interplanetary current sheet, Astrophys., J., 243, 1115, 1981.

Smith, E. J., B. T. Tsurutani, and R. L. Rosenberg, Observations of the interplanetary sector structure up to heliographic latitudes of 16°: Pioneer 11, J. Geophys. Res., 83, 717, 1978.

	Three-dimensional sketch of the heliospheric current sheet. The current sheet is shown lying near the solar equator with spiraled outward-pointing fields lying above it and inward-pointing fields lying below it. The average position of the current sheet is tilted relative to the solar equator, and the current sheet also contains folds or flutes. When the sun rotates, an observer near the ecliptic will alternately lie above and below the current sheet and will see a changing sector pattern. [From Smith et al., 1978.]
	This sketch is a computer-generated perspective plot of the heliospheric current sheet configuration expected from a flat, inclined sheet near the sun, which is convected outward by a uniform velocity solar wind. The inclination of the current sheet assumed in this diagram is 15 degrees. Positive fields will be observed above the current sheet (during every other phase of the solar cycle) and negative fields below. A stationary observer near the solar equatorial plane will see two oppositely directed sectors per solar rotation. It can be seen that both sectors will adopt the standard Parker spiral configuration. [From Jokipii and Thomas, 1981.]
	Artist's rendition of the heliospheric current sheet for a slightly inclined circular neutral line on a solar source surface. This drawing demonstrates the three-dimensional structure of the current sheet as it would evolve in a constant solar wind flow resulting in the usual two sector pattern. In practice, a four-sector per solar rotation pattern (and sometimes even higher) is quite usual implying that the 3-D shape of the HCS is even more complex than shown on this picture.