Progress Toward Implementation of the 2013 Decadal Survey for Solar and Space Physics A Midterm Assessment (2020) / Chapter Skim
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Appendix E: Progress for Science Challenges in 2013 Heliophysics Decadal Survey
Appendix E: Progress for Science Challenges in 2013 Heliophysics Decadal Survey
Pages 143-170
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From page 143... ...
• Close to the Sun, the Parker Solar Probe has set the record for closest approach to the Sun; its ongoing mission is to sample solar coronal particles and the solar electromagnetic field to understand coronal heating, solar wind acceleration, and the formation and transport of solar energetic particles. • Far from the Sun, measurements by the Voyager spacecraft (that exited the heliosphere in 2012 and 2018, respectively) , combined with Interstellar Boundary Explorer (IBEX)
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These newly developed computer models can be applied to new data, but also retrospectively to archival data so that we can efficiently learn from decades-long historical archives. TABLE E.1 The 12 Science Challenges in the 2013 Heliophysics Decadal Survey are Mapped to the Four Key Science Goals in the Decadal Survey Key Science Goal 1. Determine the origins of the Sun's activity and predict the variations in the space environment.
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From page 145... ...
They also emphasize the importance of accessible, standardized archives and the need to develop community-usable numerical tools for modeling and analysis, sometimes using artificial intelligence, including data-driven full-system models that include the space weather forecasting systems. Decadal Survey Challenge SHP-1: Determine How the Sun Generates the Quasi-Cyclical Variable Magnetic Field that Extends Throughout the Heliosphere Inside the Sun, hot, ionized gas ("plasma")
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Decadal Survey Challenge SHP-2: Determine How the Sun's Magnetic Field Creates Its Dynamic Atmosphere The last 6 years saw numerous advances in what we know of the coupling between the hot solar corona and the heliosphere, driven by both observations and numerical models that span the smallest observable scales on the Sun to the entire heliosphere. Scientists applied a systems approach, by driving numerical models with observational data, to study the corona and heliosphere as a whole.
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These comprehensive models help scientists understand the heating of the solar atmosphere as well as the mechanisms that trigger flares and CMEs. Decadal Survey Challenge SHP-3: Determine How Magnetic Energy Is Stored and Explosively Released The explosive release of magnetic energy creates a variety of phenomena that include flares, CMEs, shocks and energetic particles, and magnetospheric (sub-storms) and aurorae at Earth.
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. Decadal Survey Challenge SHP-4: Discover How the Sun Interacts with the Local Galactic Medium and Protects Earth Over the past 6 years, there have been several surprises about the boundary between the immense magnetic bubble containing our solar system and the surrounding interstellar medium.
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to the magnetic field; (c) the magnetic field strength; (d)
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Finally, in the last 6 years, data and models from solar and space physics helped characterize the space weather environment of exoplanets around other, relatively Sun-like (G-, K-, and M-type) stars.
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The analysis of many tails of comets over their observable trajectories is helping us understand solar-wind variability, specifically its turbulence, and how that evolves from near the Sun outward. • Space-weather conditions at Mars were studied with particular emphasis on the solar wind coupled to that planet's atmosphere with its weak, local magnetism. Decadal Survey Challenge SWMI-1: Establish How Magnetic Reconnection Is Triggered and How It Evolves to Drive Mass, Momentum, and Energy Transport Key Science Goal 2 of the decadal survey is to determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs.
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, or near the magnetopause in waves that are excited by the solarwind flowing by Earth's magnetic field, just as ocean waves are excited by strong atmospheric winds (via Kelvin-Helmholtz instability) . In recent years, advanced computer simulations have clarified better how reconnection is strongly driven at the subsolar magnetopause under southward IMF and also how the reconnection rate on the flanks may be significantly modified in the presence of large-scale nonlinear Kelvin-Helmholtz waves running along the magnetopause (Ma et al., 2014; 2017)
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. Decadal Survey Challenge SWMI-2: Identify the Mechanisms that Control the Production, Loss, and Energization of Energetic Particles in the Magnetosphere In Earth's inner magnetosphere, charged particles are accelerated to speeds approaching the speed of light, forming the highly dynamic region known as the Van Allen radiation belts. The variability of the radiation belts has been a long-standing mystery, and this region is important both as a laboratory for studying particle acceleration and due to its space weather impacts on the nation's space assets. NASA's twin Van Allen Probes, launched in 2012, have changed our understanding of the very structure of the radiation belts, with their high-resolution instruments and the use of a pair of probes that enables us to tell apart structures in space from evolution in time.
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. FIGURE E.7 Illustration showing the broad selection of modeling tools and results available through the Community C oordinated Modeling Center and space weather research center at NASA Goddard Space Flight Center (see https://ccmc. gsfc.nasa.gov/iswa/)
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(2013, 2018) found approximately 30 percent reductions in thermospheric density during solar minimum and approximately 15 percent reductions in global mean ionospheric electron content related primarily to the reduced solar EUV fluxes. Decadal Survey Challenge SWMI-4: Critically Advance the Physical Understanding of Magnetospheres and Their Coupling to Ionospheres and Thermospheres by Comparing Models Against Observations from Different Magnetospheric Systems Space weather is usually associated with Earth's space environment, but it is in its broader definition solar system–wide (Figure E.8)
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. tions to analyze both the differences in space weather at the innermost three terrestrial planets and the heliospheric distributions of events. Heliophysics resources have also supported investigations of space weather conditions at Mars, which concern how the solar wind interacts with its atmosphere and have significance for ongoing planning for human missions.
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From page 157... ...
Waves are also generated in the dynamics of the polar vortex at stratospheric altitudes. All these wave phenomena can modify high-atmospheric properties, including ionospheric properties, far from the latitudes where they originally formed, which, in turn, couple to space weather phenomena further out. • Drivers of long-term trends in upper atmospheric properties are better clarified using ever more sophisticated global circulation models to reveal the dynamic effects from solar variability, the cooling influence of anthropogenic methane and carbon dioxide, and even the top-down coupling of atmospheric changes resulting from the long-term change of the terrestrial magnetic field, of which the shift of the magnetic poles is one consequence.
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This result has substantial implications on our understanding of how geomagnetic storms affect the tenuous atmosphere within which satellites orbit. Bright visible auroras are produced by energetic particles flowing along magnetic field lines into the upper atmosphere.
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These temperature enhancements are associated with electrojet turbulence introduced by instabilities from large velocity differences between the electrons following the magnetic field and the ions scattered off the field by collisions. Although long considered a local phenomenon, the extent of enhanced electric fields across the high latitudes during geomagnetic storms suggests that this phenomenon can influence the largescale, high-latitude ionospheric current system.
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conceived the dynamic life cycle of meteoric metals via deposition, transport, chemistry, and wave dynamics for thermospheric iron layers with gravity waves. Decadal Survey Challenge AIMI-3: Understand How Forcing from the Lower Atmosphere via Tidal, Planetary, and Gravity Waves Influences the Ionosphere and Thermosphere The vertical transport of energy and momentum by atmospheric waves is a fundamental process in planetary atmospheres and -- on Earth -- links tropospheric weather with the space weather of the ionosphere and thermosphere. The modulation of input of energy into the troposphere and stratosphere due to Earth's rotation excites a range of planetary-scale thermal tides, while surface topography, unstable flows, and cloud dynamics excite waves all the way down to scales of only a few kilometers, introducing a range of periods from several weeks to a few minutes.
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how upper vortex image only and the Geophysical Research Letters 10.1002/2015GL065903 scale to the right, but shorten it Figure 3. Concentric gravity wave image in VIIRS/DNB measurements on 4 April 2014 at 8:08:59 UTC.
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, the new models perform much better in nowcasting the state of the neutral and ionized atmosphere, an important milestone towards space weather predictability. Using the new data assimilation research testbed, measurements from ground level up to 110 km have been used in the Whole Atmosphere Community Climate Model (WACCM)
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(2016) predicted that long-term changes in Earth's magnetic field directly impact the ionosphere and thermosphere via changes in ion-neutral interactions and also the atmosphere below through a top-down coupling, with polar surface temperature changes of up to about 1.3 K between 1900 and 2000.
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Journal of Geophysical Research: Space Physics 121(4)
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Journal of Geophysical Research: Space Physics 122(4)
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2014. Anomalous expansion of coronal mass ejections during solar cycle 24 and its space weather implications.
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2015. Plasma and magnetic field charac teristics of solar coronal mass ejections in relation to geomagnetic storm intensity and variability.
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Journal of Geophysical Research: Space Physics 121(4)
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Journal of Geophysical Research: Space Physics 121:7204.
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Journal of Geophysical Research: Space Physics 120(8)
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