A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals

Details A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals

Oct 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011pepi..188..214r&link_type=abstract

Physics of the Earth and Planetary Interiors, Volume 188, Issue 3, p. 214-234.

Physics

Scientific paper

We couple a low order αω dynamo model to a shell model of turbulence, with the dynamo α-effect being identified with the helicity of the shell model. Fluctuations ('noise') in this term lead to lognormal-like statistics in the magnetic field, as was noted for inter-reversal duration by Ryan and Sarson (2007). Here we extend the analysis to shorter time-scale field variations (viz. Virtual Axial Dipole Moments, VADMs), and find that a lognormal distribution is also a significant fit for this quantity, both for the output from our model and for the observed paleomagnetic data. This shared lognormality - which Ryan and Sarson (2007) argued arose from a common source in terms of 'multiplicative noise' in the underlying dynamo mechanism - makes the synthetic and observed data comparable; we also note some similarities in the patterns of VADM fluctuations (including asymmetric decay and recovery, epitomised in an extreme form by the controversial 'saw-tooth' pattern) and in reversal inter-event times (chrons) of widely varying duration. We describe the dynamics behind our coupled model, and discuss the effect of certain model parameters on the synthetic chron durations, including the occurrence of superchrons. Implications for the observed geomagnetic field behaviour are discussed.

Affiliated with

Also associated with

No associations

Rating

A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A coupled low order dynamo/turbulent shell model for geomagnetic field variations and reversals will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1673062