Investigating Magnetic Flux Emergence with Modeling and Observations to Understand the Onset of Major Solar Eruptions
ROSES ID: NNH17ZDA001N Selection Year: 2017
Program Element: Focused Science Topic
Principal Investigator: Mark Linton
Affiliation(s): Naval Research Laboratory
Schuck, Peter W Co-I NASA Goddard Space Flight Center
Leake, James Edward Co-I/Institutional PI NASA Goddard Space Flight Center
Torok, Tibor Co-I Predictive Science Inc.
Science Goals and Objectives
We propose to address the Living with a Star Focused Science Topic (LWS FST):
``Understanding the Onset of Major Solar Eruptions.'' To achieve this, we propose
to investigate the injection of free energy and helicity in the corona, and the
subsequent triggering of major solar eruptions, focusing on the emergence of
magnetic flux into the corona. Our goal is to understand how emerging magnetic
flux either injects helicity and free energy into the corona to generate eruptions,
or destabilizes pre-existing structures so that they erupt. To achieve this, we
will investigate flux-emergence sources of active region eruptive capacity by
simulating the emergence of magnetic flux into the corona in eruptive configurations.
In parallel, we will use these simulations to develop observables for predicting
the occurrence and timing of eruptions. We will use FST team observations to
test these metrics on both eruptive and non-eruptive ARs.
Our proposed methodology is to simulate eruptions driven by flux emergence in two
prominent theoretical eruption scenarios: the formation of unstable sheared fields
and flux ropes via flux emergence; and the destabilization of pre-existing sheared
fields and flux ropes via flux emergence. The configurations studied will include
both the ``breakout'' and the ``torus instability'' eruption paradigms. To simulate
these scenarios, we will use both the LaRe3d (Lagrangian Remap in Three Dimensions)
code and the MAS (Magnetohydrodynamics outside A Sphere) code.
With these simulations and analyses, we propose to answer the following questions:
Question 1: How does flux emergence inject free energy and helicity into the corona?
What are the critical magnetic configurations which are built up by emerging magnetic
flux into pre-existing coronal fields? We will use our simulations to determine the
observable signatures of this buildup of free energy and helicity by flux emergence,
and to determine which simulated configurations of emerging flux do, or do not, lead
Question 2: How does flux emergence trigger eruptions?
What aspects of emerging flux act as the trigger which sets off an eruption?
By freezing the emergence of flux at earlier and earlier times in our simulations
during eruptions until the eruption no longer occurs, we will isolate the time at
which this trigger is injected into the corona.
Question 3: How can the models explored in this project be used to develop predictive
observables for eruptions?
Using the modeling results, we will establish a well-defined set of rules for
determining, from observed magnetic field and velocity signatures, when an
eruption-driving flux emergence event is occurring on the Sun.
We will combine the insight gained from answering these questions to
develop an understanding of which key factors energize pre-eruptive active regions
and lead to the onset of major solar eruptions. This project will therefore advance
the LWS goal of ``Developing physics based understanding for predicting electromagnetic,
particle and plasma outputs driving the solar system environment...''
(Strategic Science Area 0).
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