Global Forces in Eruptive Solar Flares: The Lorentz Force Acting on the Solar Atmosphere and the Solar Interior
By George H. Fisher, D. Bercik, B. Welsch, Hugh S. Hudson. 2010
146 citations recorded by the source corpus.
We compute the change in the Lorentz force integrated over the outer solar atmosphere implied by observed changes in vector magnetograms that occur during large, eruptive solar flares. This force perturbation should be balanced by an equal and opposite force perturbation acting on the solar photosphere and solar interior. The resulting expression for the estimated force change in the solar interior generalizes the earlier expression presented by Hudson, Fisher, and Welsch (Astron. Soc. Pac. CS-383, 221, 2008), providing horizontal as well as vertical force components, and provides a more accurate result for the vertical component of the perturbed force. We show that magnetic eruptions should result in the magnetic field at the photosphere becoming more horizontal, and hence should result in a downward (toward the solar interior) force change acting on the photosphere and solar interior, as recently argued from an analysis of magnetogram data by Wang and Liu (Astrophys. J. Lett. 716, L195, 2010). We suggest the existence of an observational relationship between the force change computed from changes in the vector magnetograms, the outward momentum carried by the ejecta from the flare, and the properties of the helioseismic disturbance driven by the downward force change. We use the impulse driven by the Lorentz-force change in the outer solar atmosphere to derive an upper limit to the mass of erupting plasma that can escape from the Sun. Finally, we compare the expected Lorentz-force change at the photosphere with simple estimates from flare-driven gasdynamic disturbances and from an estimate of the perturbed pressure from radiative backwarming of the photosphere in flaring conditions.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/c9b63c9ec3565c397325ed3b244ddfcba613ea13
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In Astronomy and Astrophysics
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Citations in the corpus
- Predicting Solar Flares Using SDO/HMI Vector Magnetic Data Products and the Random Forest Algorithm (2017, methodology): “Lorentz was produced based on SHARP data to include estimations of integrated Lorentz forces (Sun et al. 2014), which can help diagnose dynamic processes of ARs (Fisher et al. 2012).”
- WHY IS THE GREAT SOLAR ACTIVE REGION 12192 FLARE-RICH BUT CME-POOR? (2015, methodology): “Along this line, Fisher et al. (2012) argue that one can use the photospheric integral of Maxwell stress tensor to estimate the total Lorentz force in a carefully selected volume.”
- SOLAR FLARE PREDICTION USING SDO/HMI VECTOR MAGNETIC FIELD DATA WITH A MACHINE-LEARNING ALGORITHM (2014, background): “Seven of these parameters characterize the Lorentz force exerted by an AR on the solar atmosphere and are adapted from Fisher et al. (2012), who find that solar activity may be associated with a Lorentz force impulse at the photosphere.”