Open AccessObservations of a switch‐off shock in interplanetary space
Author(s) -
Feng H. Q.,
Lin C. C.,
Chao J. K.,
Wu D. J.,
Lyu L. H.,
Lee L. C.
Publication year - 2008
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007ja012864
Subject(s) - mach number , physics , shock (circulatory) , shock wave , mechanics , solar wind , interplanetary magnetic field , interplanetary spaceflight , moving shock , magnetic field , geophysics , medicine , quantum mechanics
An interplanetary slow shock event was observed by Voyager 1 on 1 November 1980. The structure is identified to be a switch‐off shock which is a special type of slow shocks by fitting the Rankine‐Hugoniot relations. The shock has the following properties: (1) Observed parameters meet the R‐H relations well. (2) Number density increases from the upstream region to the downstream region. On the contrary, total magnetic field strength decreases. (3) The slow‐mode Mach number is greater than unity in the preshock state and less than unity in the postshock state. (4) The normal Alfvén‐Mach number is almost equal to 1 in the preshock state; the tangential component of the downstream magnetic field is “turned off,” leaving only a minor quantity along the shock normal.