810 research outputs found
Creating an Effective Social-Emotional Learning Program at the High School Level: A School Improvement Plan
This school improvement plan details the importance of creating an effective social and emotional learning (SEL) program for high school students in the wake of the COVID-19 pandemic and the current mental health crisis among teenagers. Current research points to SEL programs for improvement in nearly all areas for students, whether it be academic achievement, attitude and behavior, resilience, or overall connectedness with peers; furthermore, research also indicates decreases in student aggression and emotional distress. With those findings in mind, this plan was created to focus on the improvement of two specific SEL skills: social awareness and relationship skills. The plan outlines a two-year initiative to educate staff and students about SEL, to develop an SEL curriculum appropriate for high school students, and to foster a positive school culture and climate
Solar convection and magneto-convection simulations
Magneto-convection simulations with two scenarios have been performed: in one, horizontal magnetic field is advected into the computational domain by fluid entering at the bottom. In the other, an initially uniform vertical magnetic
field is imposed on a snapshot of non-magnetic convection and allowed to evolve. In both cases, the field is swept into the intergranular lanes and the boundaries of the
underlying mesogranules. The largest field concentrations at the surface reach pressure balance with the surrounding gas. They suppress both horizontal and vertical flows, which reduces the heat transport. They cool, become evacuated and their optical depth unity surface is depressed by several hundred kilometers. Micropores form, typically where a small granule disappears and surrounding flux tubes squeeze into its previous location
The Three-dimensional Evolution of Rising, Twisted Magnetic Flux Tubes in a Gravitationally Stratified Model Convection Zone
We present three-dimensional numerical simulations of the rise and
fragmentation of twisted, initially horizontal magnetic flux tubes which evolve
into emerging Omega-loops. The flux tubes rise buoyantly through an
adiabatically stratified plasma that represents the solar convection zone. The
MHD equations are solved in the anelastic approximation, and the results are
compared with studies of flux tube fragmentation in two dimensions. We find
that if the initial amount of field line twist is below a critical value, the
degree of fragmentation at the apex of a rising Omega-loop depends on its
three-dimensional geometry: the greater the apex curvature of a given
Omega-loop, the lesser the degree of fragmentation of the loop as it approaches
the photosphere. Thus, the amount of initial twist necessary for the loop to
retain its cohesion can be reduced substantially from the two-dimensional
limit. The simulations also suggest that as a fragmented flux tube emerges
through a relatively quiet portion of the solar disk, extended crescent-shaped
magnetic features of opposite polarity should form and steadily recede from one
another. These features eventually coalesce after the fragmented portion of the
Omega-loop emerges through the photosphere.Comment: 17 pages, 17 figures, uses AAS LaTeX macros v5.0. ApJ, in pres
Estimating Electric Fields from Vector Magnetogram Sequences
Determining the electric field (E-field) distribution on the Sun's
photosphere is essential for quantitative studies of how energy flows from the
Sun's photosphere, through the corona, and into the heliosphere. This E-field
also provides valuable input for data-driven models of the solar atmosphere and
the Sun-Earth system. We show how Faraday's Law can be used with observed
vector magnetogram time series to estimate the photospheric E-field, an
ill-posed inversion problem. Our method uses a "poloidal-toroidal
decomposition" (PTD) of the time derivative of the vector magnetic field. The
PTD solutions are not unique; the gradient of a scalar potential can be added
to the PTD E-field without affecting consistency with Faraday's Law. We present
an iterative technique to determine a potential function consistent with ideal
MHD evolution; but this E-field is also not a unique solution to Faraday's Law.
Finally, we explore a variational approach that minimizes an energy functional
to determine a unique E-field, similar to Longcope's "Minimum Energy Fit". The
PTD technique, the iterative technique, and the variational technique are used
to estimate E-fields from a pair of synthetic vector magnetograms taken from an
MHD simulation; and these E-fields are compared with the simulation's known
electric fields. These three techniques are then applied to a pair of vector
magnetograms of solar active region NOAA AR8210, to demonstrate the methods
with real data.Comment: 41 pages, 10 figure
Subsurface magnetic field and flow structure of simulated sunspots
We present a series of numerical sunspot models addressing the subsurface
field and flow structure in up to 16 Mm deep domains covering up to 2 days of
temporal evolution. Changes in the photospheric appearance of the sunspots are
driven by subsurface flows in several Mm depth. Most of magnetic field is
pushed into a downflow vertex of the subsurface convection pattern, while some
fraction of the flux separates from the main trunk of the spot. Flux separation
in deeper layers is accompanied in the photosphere with light bridge formation
in the early stages and formation of pores separating from the spot at later
stages. Over a time scale of less than a day we see the development of a large
scale flow pattern surrounding the sunspots, which is dominated by a radial
outflow reaching about 50% of the convective rms velocity in amplitude. Several
components of the large scale flow are found to be independent from the
presence of a penumbra and the associated Evershed flow. While the simulated
sunspots lead to blockage of heat flux in the near surface layers, we do not
see compelling evidence for a brightness enhancement in their periphery. We
further demonstrate that the influence of the bottom boundary condition on the
stability and long-term evolution of the sunspot is significantly reduced in a
16 Mm deep domain compared to the shallower domains considered previously.Comment: 20 pages, 14 figures, 4 animations, accepted for publication in Ap
Mechanism of spontaneous formation of stable magnetic structures on the Sun
One of the puzzling features of solar magnetism is formation of long-living
compact magnetic structures; such as sunspots and pores, in the highly
turbulent upper layer of the solar convective zone. We use realistic radiative
3D MHD simulations to investigate the interaction between magnetic field and
turbulent convection. In the simulations, a weak vertical uniform magnetic
field is imposed in a region of fully developed granular convection; and the
total magnetic flux through the top and bottom boundaries is kept constant. The
simulation results reveal a process of spontaneous formation of stable magnetic
structures, which may be a key to understanding of the magnetic
self-organization on the Sun and formation of pores and sunspots. This process
consists of two basic steps: 1) formation of small-scale filamentary magnetic
structures associated with concentrations of vorticity and whirlpool-type
motions, and 2) merging of these structures due to the vortex attraction,
caused by converging downdrafts around magnetic concentration below the
surface. In the resulting large-scale structure maintained by the converging
plasma motions, the magnetic field strength reaches ~1.5 kG at the surface and
~6 kG in the interior; and the surface structure resembles solar pores. The
magnetic structure remains stable for the whole simulation run of several hours
with no sign of decay.Comment: 13 pages, 4 figures, submitted to the Astrophysical Journa
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