EGU22-9790
https://doi.org/10.5194/egusphere-egu22-9790
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Rapid Auroral Wandering During the Laschamps Event

Agnit Mukhopadhyay1,2,3, Sanja Panovska4, Michael Liemohn1, Natalia Ganjushkina1, Ilya Usoskin5, Michael Balikhin6, Daniel Welling7, and Katherine Garcia-Sage2
Agnit Mukhopadhyay et al.
  • 1University of Michigan, Climate and Space Sciences and Engineering, United States of America (agnitm@umich.edu)
  • 2NASA Goddard Space Flight Center, United States of America
  • 3American University, Washington DC, United States of America
  • 4GFZ German Research Centre for Geosciences, Potsdam, Germany
  • 5University of Oulu, Department of Physics, Finland
  • 6University of Sheffield, Department of Automatic Control and Systems Engineering, United Kingdom
  • 7University of Texas at Arlington, Department of Physics, United States of America

41 thousand years ago, the Laschamps geomagnetic excursion caused Earth’s magnetic field to drastically diminish to ~4% of modern values and modified its dipole-dominated structure. While the impact of this geomagnetic event on environmental factors and human lifestyle has been contemplated to be linked with modifications in the geospace environment, no concerted investigation has been conducted to study this until recently.

We present an initial investigation of the global space environment and related plasma environments during the several phases of the Laschamps event using an advanced multi-model approach. We use recent paleomagnetic field models of this event to study the paleomagnetosphere with help of the global magnetohydrodynamic model BATS-R-US. Here we go beyond a simple dipole approximation but consider a realistic geomagnetic field configuration. The field is used within the global magnetohydrodynamic model BATS-R-US to generate the magnetosphere during discrete epochs spanning the peak of the event. Since solar conditions have remained fairly constant over the last ~100k years, modern estimates of the solar wind were used to drive the model. Finally, plasma pressure and currents generated by BATS-R-US at their inner boundary are used to compute auroral fluxes using a stand-alone version of the MAGNIT model, an adiabatic kinetic model of the aurora.

Our results show that changes in the geomagnetic field, both in strength and the dipole tilt angle, have profound effects on the space environment and the ensuing auroral pattern. Magnetopause distances during the deepest phase of the excursion match previous predictions, while high-resolution mapping of magnetic fields allow close examination of magnetospheric structure for non-dipolar configurations. Temporal progression of the event also exhibits rapid locomotion of the auroral region over ~250 years along with the movement of the geomagnetic poles. Our estimates suggest that the aurora extended further down, with the center of the oval located at near-equatorial latitudes during the peak of the event. While the study does not find evidence of any link between geomagnetic variability and habitability conditions, geographic locations of the auroral oval coincide with early human activity in the Iberian peninsula and South China Sea.

How to cite: Mukhopadhyay, A., Panovska, S., Liemohn, M., Ganjushkina, N., Usoskin, I., Balikhin, M., Welling, D., and Garcia-Sage, K.: Rapid Auroral Wandering During the Laschamps Event, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9790, https://doi.org/10.5194/egusphere-egu22-9790, 2022.

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