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“Magnetic dynamos: the Earth, the Sun, and laboratory models
of the Earth´s magnetic field."
Thursday, 14 Jan 2021
Video-Recording for any system with MP4-support
- Video.mp4 (ca.292 Mb)
- Video_with_eng_sub.mp4 (ca. 294 Mb)
15:15 – 16:15
During the last solar maximum around 2014, we saw a host of x-class flares
and coronal mass ejections from the sun. We experienced few problems this time
on Earth due in part to the Earth's magnetic field, which shields us from much
of the Sun's charged particle radiation. Surprisingly, that field has weakened
throughout recorded history. The origin and dynamics of the magnetic fields
of the Earth, Sun, gas giants, and nearly every massive astrophysical object
raise numerous questions not completely resolved by existing theoretical,
computational and experimental work.
The next maximum of solar activity should be around 2024-2025.
In this talk I'll review the basics of the Earth's magnetic field, its reversals,
recent changes to the magnetic field, and an overview of the solar cycle.
Then we will discuss how laboratory experiments can help to understand
the processes. By using liquid sodium models of the Earth's core, different
international groups seek to better understand what determines the Earth's
magnetic field strength, pattern and dynamics by probing the effects of
turbulence, Lorentz forces and rotation on core dynamics.
While it is not possible to match every aspect of core dynamics in the lab,
the experiments seek a comparable force balance among rotation, magnetic
fields and advection.
Speaker today: Daniel Lathrop (University of Maryland)
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