Identification of interplanetary tangential and rotational discontinuities

Abstract

Discontinuities in the interplanetary magnetic field detected by the Mariner 5 magneto,meter have been analyzed to distinguish tangential and rotational discontinuities. The method used was based on finding the field component normal to the plane of the discontinuities that vanishes for tangential discontinuities and is nonzero for rotational discontinuities. The normal to each discontinuity was obtained by a variance analysis of the field vectors on both sides and within the current layer to find the direction of minimum field variation. Supplementary information concerning the existence or absence of changes in field magnitude across the discontinuities was also used to permit an unambiguous identification of both tangential and rotational discontinuities. Slightly less than one half of the 118 discontinuities analyzed could not be classified because neither the normal component nor the changes in field magnitude were statistically significant owing to errors in the field measurements and in finding the normal direction. The 44 rotational discontinuities that were finally identified did not exhibit changes in field magnitude in excess of 20%, an uncertainty that is consistent with the anticipated maximum error in measurement. ß ß ß eee ß ß ß ß SMITH' INTERPLANETARY DISCONTINUITIES I ß ß e e ß ß ee ß

What is the best method to calculate the solar wind propagation delay?

“…Landau and Lifshitz, 1960;Hudson, 1970), but also experimentally (e.g. Colburn and Sonett, 1966;Siscoe et al, 1968;Turner and Siscoe, 1971;Smith, 1973).…”

“…Colburn and Sonett, 1966;Smith, 1973), i.e. a discontinuity where there is no net plasma flow across the discontinuity ( V ·n=0), and where the average magnetic field is tangential to the discontinuity ( B ·n=0).…”

Nonlinear Alfvén waves, discontinuities, proton perpendicular acceleration, and magnetic holes/decreases in interplanetary space and the magnetosphere: intermediate shocks?

“…The latter was done using the minimum variance method (Sonnerup and Cahill, 1967). Smith (1973b) sorted discontinuities into a two-dimensional phase space. Discontinuities with large magnetic field components along the normal direction have rotational discontinuity properties (a sharply crested Alfvén wave).…”

Ion distributions in large magnetic holes in the fast solar wind

“…Both of the long-duration holes were bounded by discontinuities. A principal-axis analysis [Sonnerup and Cabill, 1967;Smith, 1973;Lepping and Behannon, 1980] of these four discontinuities suggests that the first (at 0824 UT)and the last (at 0936 UT) were tangential discontinuities, the second at (0854 UT) was probably a rotational discontinuity, while the normal to the third (at 0914 UT) could not be determined because the directional change was largely confined to a line rather than tracing out a planar arc. A significant difference between this pair of holes and the holes studied by Winterhalter et al [1994,2000] is that the field-rotated through large angles across both the long-duration holes (see Table 1).…”