Open AccessUse of single‐component wind speed in Rankine‐Hugoniot analysis of interplanetary shocks
Author(s) -
Vorotnikov Vasiliy S.,
Smith Charles W.,
Farrugia Charles J.,
Meredith Calum J.,
Hu Qiang,
Szabo Adam,
Skoug Ruth M.,
Cohen Christina M. S.,
Davis Andrew J.,
Yumoto Kiyohumi
Publication year - 2011
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1029/2010sw000631
Subject(s) - shock (circulatory) , solar wind , physics , interplanetary magnetic field , interplanetary spaceflight , magnetopause , coronal mass ejection , geophysics , aerospace engineering , mechanics , magnetic field , medicine , quantum mechanics , engineering
We have extended and deployed a routine designed to run independently on the Web providing real‐time analysis of interplanetary shock observations from L 1 . The program accesses real‐time magnetic field, solar wind speed, and proton density data from the Advanced Composition Explorer (ACE) spacecraft, searches for interplanetary shocks, analyzes shocks according to the Rankine‐Hugoniot (R‐H) jump conditions, and provides shock solutions on the Web for space weather applications. Because the ACE real‐time data stream contains the wind speed but not the three‐component wind velocity, we describe modifications to the R‐H analysis that use the scalar wind speed and show successful results for analyses of strong interplanetary shocks at 1 AU. We compare the three‐component and one‐component solutions and find the greatest disagreement between the two rests in estimations of the shock speed rather than the shock propagation direction. Uncertainties in magnetic quantities such as magnetic compression and shock normal angle relative to the upstream magnetic field show large uncertainties in both analyses when performed using an automated routine whereas analyses of the shock normal alone do not. The automated data point selection scheme, together with the natural variability of the magnetic field, is inferred to be a problem in a few instances for this and other reasons. For a broad range of interplanetary shocks that arrive 30 to 60 min after passing L 1 , this method will provide 15 to 45 min of advanced warning prior to the shock's collision with the Earth's magnetopause. The shock, in turn, provides advance warning of the approaching driver gas.