Research Highlights

Research Highlights

A selection of highlights culled from publications by HAO staff.

WACCM-X daily column

Influence of Stratosphere Polar Vortex Variability on the Mesosphere, Thermosphere, and Ionosphere

Nick Pedatella used WACCM-X to investigate the influence of stratosphere polar vortex variability on the mesosphere, thermosphere, and ionosphere during Northern Hemisphere winter. Based on 40 simulated Northern Hemisphere winters, the mesosphere and lower thermosphere (MLT) residual circulation is found to depend on whether the stratosphere polar vortex is strong or weak.

Ribbon evolution

Hybrid data-driven magnetofrictional and magnetohydrodynamic simulations of an eruptive solar active region

Andrey N. Afanasyev, Yuhong Fan, Maria D. Kazachenko, and Mark C.M. Cheung present first results of the hybrid data–driven magnetofrictional (MF) and data–constrained magnetohydrodynamic (MHD) simulations of solar active region NOAA 11158, which produced an X-class flare and coronal mass ejection on 2011 February 15. We conclude that the combination of the data–driven MF and data–constrained MHD simulations is a useful practical tool for understanding the 3D magnetic structures of real solar ARs that are unobservable otherwise.

small satellite technology and solar sailing propulsion

Science opportunities with solar sailing smallsats

Sarah Gibson, et al. witnessed how the synergy of small satellite technology and solar sailing propulsion enables new missions. Together, small satellites with lightweight instruments and solar sails offer affordable access to deep regions of the solar system, also making it possible to realize hard-to-reach trajectories that are not constrained to the ecliptic plane. 

Synthetic AIA

Eruption of a Magnetic Flux Rope in a Comprehensive Radiative Magnetohydrodynamic Simulation of flare-productive active regions

Feng Chen, Matthias Rempel, and Yuhong Fan present a radiative magnetohydrodynamic simulation that includes sufficiently realistic physics to allow for the synthesis of remote sensing observables that can be quantitatively compared with observations. The model helps to shed light on questions of where and when the a flux rope may form and how the magnetic structures in an eruption are related to observable emission properties.

Coronal dimming

A Comprehensive Radiative Magnetohydrodynamics Simulation of Active Region Scale Flux Emergence from the Convection Zone to the Corona

Feng Chen, Matthias Rempel, and Yuhong Fan present a comprehensive radiative magnetohydrodynamic simulation of the quiet Sun and large solar active regions. This study provides a comprehensive view of the active region corona, such as coronal loops of various lengths and temperatures, mass circulation by evaporation and condensation, and eruptions from jets to large-scale mass ejections.

Scatter plot semidiurnal solar (S2) and semidiurnal lunar (L2) geomagnetic tides

Impact of strong and weak stratospheric polar vortices on geomagnetic solar and lunar tides

N. M. Pedatella, et al. investigate the impact of strong and weak stratospheric polar vortices on geomagnetic semidiurnal solar and lunar tides during Northern Hemisphere (NH) winters using ground-based magnetic field observations at the Huancayo (-12.05° N, 284.67° E; magnetic latitude: -0.6° N) equatorial observatory.

McIntosh style coronal hole maps

A Mosaic of the inner heliosphere:

Sarah E. Gibson, et al. provide an expansive mosaic of observations spanning from the Sun, through interplanetary space, to the magnetospheric response and subsequent effects on the ionosphere-thermosphere-mesosphere (ITM) system. To accomplish this, a diverse set of observational datasets are utilized and focused on two long-lived coronal holes and their varying impact in sculpting the heliosphere and driving of the magnetospheric system.

Ground Truth and Data Driven simulations

Data-driven Radiative Magnetohydrodynamics Simulations with the MURaM Code

Feng Chen, Mark C.M. Cheung, Matthias Rempel, and Georgios Chintzoglou present a method of conducting data-driven simulations of solar active regions and flux emergence with the MURaM radiative magnetohydrodynamics (MHD) code. This method helps to understand the evolution of magnetic field in a more realistic coronal environment and to link the magnetic structures to observable diagnostics.

Comparison of Bz at optical depth

Small-scale dynamos: From idealized models to solar and stellar applications

Matthias Rempel, Tanayveer Bhatia, Luis Bellot Rubio, and Maarit J. Korpi-Lagg review small-scale dynamo processes that are responsible for magnetic field generation on scales comparable to and smaller than the energy carrying scales of turbulence. We provide a review of critical observation of quiet Sun magnetism, which have provided strong support for the operation of a small-scale dynamo in the solar photosphere and convection zone.