A B-field North event is defined as an extended period of magnetic field oriented northward
Presently the catalog includes only those BzN events that extend for periods longer than 4 hours, within which only brief southward excurtions may occur.
A B-field South event is defined as an extended period of magnetic field oriented southward
Presently the catalog includes under this entry only those BzS events that extend for periods longer than 4 hours, within which only brief Northward violations may occur.
Included are the observed events characterized by a sudden sign change and large amplitude variation in Ey (Ey=Bz*Vx) (the dawn to dusk component of the interplanetary electric field).
An HSS is defined as a SW flow moving outward from the Sun with a high speed (usually a bulk velocity Vb>500 Km/sec), accompanied by low density and high temperature protons.
Presently the catalog includes only those HSS events that extended for periods longer than a day.
An Interplanetary Magnetic Cloud is defined as (1) a smooth variation of the magnetic field direction, through a large angle; (2) strong magnetic fields; and (3) low ion temperature and low proton beta; all occurrring on a time scale of about 1 day or so.
Region of approximately half a day or longer showing unusually high magnetic and plasma pressures.
An IS is defined in term of simultaneous changes in the bulk velocity (Vb) of the SW ions, their thermal velocity (Vth), and density (n) as well as the magnitude of the magnetic field (|B|), (and sometimes its direction), so that the Rankine-Hugoniot equations are expected to be satisfied for the event. Fast forward shocks, those most commonly seen in the interplanetary medium at 1 AU, are identified by positive changes in all of these quantities in time. Strong IS accompanied by a Southward oriented B-field have been associated with the observance of strong geomagnetic storms.
The catalog contains only "candidates" for the IS category, based in the observations of the sudden change in the B-field and plasma quantities that within the resolution of the available KPs can be interpreted as being consistent with an interplanetary shock.
Only those periods of LSS when the Vb<330Km/sec are included.
An occassional feature of a LSS is the presence of multiple SBCs (see def. below), and PC disruptions.
These are PCs other than IS. PC is defined as the sudden or gradual change (i.e. over a short period of time; usually less than an hour) in the type of the SW pressure (+ or -), i.e., between kinetic and the magnetic field pressures. There may or may not be pressure equilibrium accross this region during the change.
A SBC is identified by an usually rapid change in field direction by 180+/-60 Degs. such that the field goes from one relatively stable direction (over several days) to another after the change(s).
Sometimes this transition ocurrs after a large (and odd) number of such crossings, for many hours. Commonly there is a brief dip in field intensity (magnetic hole) at a crossing.
Events/Information deemed relevant to Solar, SW, or magnetospheric studies but failing to fit the other categories are added to the catalog under the MISC category.
Hundhausen, A.J., 1972, Coronal Expansion and Solar Wind. Berlin: Springer-Verlag. Kivelson, M.G., and Russell, C.T., 1995, Introduction to Space Physics. e.g. section: The Solar Wind, by A.J. Hundhausen. New York, NY: Cambridge University Press. Burlaga, L.F., 1995, Interplanetary Magnetohydrodynamics, New York, NY: Oxford University Press.
Last updated: Dec. 8, 1995