Premium
Core field acceleration pulse as a common cause of the 2003 and 2007 geomagnetic jerks
Author(s) -
Chulliat A.,
Thébault E.,
Hulot G.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl042019
Subject(s) - jerk , earth's magnetic field , core (optical fiber) , acceleration , geodesy , physics , pulse (music) , geomagnetic secular variation , field (mathematics) , magnetic field , geology , optics , classical mechanics , detector , mathematics , geomagnetic storm , quantum mechanics , pure mathematics
Using observatory data, we report the detection of a geomagnetic jerk in 2007, which we relate to a jump in the second derivative of the geomagnetic field previously noted in satellite data. Although not of worldwide extent, this jerk is very intense in the South Atlantic region. Using the CHAOS‐2 model, we show that both this jerk and the previous 2003 jerk are caused by a single core field acceleration pulse reaching its maximum power near 2006.0. This pulse seems to be simultaneously occurring in several regions of the core surface where it corresponds to dominant n = 5 and 6 spherical harmonic modes. Geometrical attenuation explains why the 2003 and 2007 jerks are local and not fully synchronized at the Earth's surface. Our results suggest that this core field acceleration pulse is the relevant phenomenon to be investigated from the point of view of core dynamics, rather than the jerks themselves.