Directional discontinuities in the interplanetary magnetic field

Abstract

It is shown that the interplanetary magnetic field has different characteristics on different scales, and it is noted that a given physical theory may not be applicable o r relevant on all scales. Four scales a r e defined in terms of time intervals on which the data may be viewed. Many discontinuities in the magnetic field direction are seen on the mesoscale (~4 days, *l AU). The characteristics of such directional discontinuities which were observed by Pioneer 6 during the

Heliosheath Magnetic Field and Plasma Observed by Voyager 2 During 2012 in the Rising Phase of Solar Cycle 24

“…The current sheets associated with tangential discontinuities were first observed in the solar wind at 1 au by Siscoe et al (1968) and Burlaga (1969), who found that they have thicknesses 10 proton Larmor radii, R L . Current sheets associated with tangential discontinuities observed at 1 au were modeled by Lemaire & Burlaga (1976), who modeled them as boundary layers across which the sum of the gas pressure, magnetic pressure, and electric field pressure is constant and whose internal structure is described by the Vlasov equation and Maxwellʼs equations.…”

Heliocentric distance dependence of the interplanetary magnetic field

“…(1968), Belcher andSolodyna (1975), Burlaga (1969, 1971a,b) Turner and Siscoe (1971, Smith (1973a,b), and others. These studies have shown that discontinuities pass a spacecraft at the rate of approximately one per hour at 1 AU.…”

Large velocity discontinuities in the solar wind

“…observations t h a t w tends t o be near 9 0 , and t h a t there a r e no small a ' s a t uD's, even though Burlaga (1968b) has shown t h a t i n general d i r e c t i o n a l d i s c o n t i n u i t i e s with small w's a r e most probable, may be explained by (9). For example, suppose t h a t near t h e sun there are UD'S with VC<VA; then (9) may be s a t i s f i e d f o r uD's with both large and small d i r e c t i o n a l d i s c o n t i n u i t i e s .…”