National Aeronautics and Space Administration

Living With A Star

Targeted Research and Technology

Observations and Modeling of Alfven Waves in the low Atmosphere

ROSES ID: NNH07ZDA001N      Selection Year: 2008      

Program Element: Focused Science Topic

Principal Investigator: Bart De Pontieu

Project Member(s):
McIntosh, Scott William Co-I National Center for Atmospheric Research
Hansteen, Viggo Haraldson Co-I University of Oslo
Carlsson, Mats Co-I University of Oslo

Summary:

Alfven waves have long been invoked as a possible mechanism for the heating of the solar corona and the acceleration of the solar wind. Using the unprecedented spatial (0.2arcsec) and temporal resolution (5s) of Hinode/SOT and 3D MHD simulations, we have recently found the first unambiguous evidence in the lower solar atmosphere of Alfven waves that carry an energy flux large enough to accelerate the solar wind. These waves have longer periods (100-500s) than the high-frequency kHz waves previously assumed in many models and observations of the solar wind. Our results directly support recent models based on low-frequency waves.



We propose to use an integrated approach of Hinode/SOT-EIS, SUMER and TRACE/AIA observations, Monte Carlo simulations and advanced radiative 3D MHD simulations to determine the source, propagation, and impact of these Alfven waves. We will directly constrain input parameters of solar wind models such as the Alfven wave amplitudes, periods, and energy flux (for quiet Sun, coronal hole and active regions) by using imaging and Dopplergram observations from photosphere through corona, as well as advanced radiative 3D MHD models that include a region from the convection zone to the corona.



Our results will lead to a much improved understanding of what drives the quiescent solar wind, an important step in improving predictions of CME propagation and impact on the Earth's space environment. Modellers will be able to use our results to pin down crucial details of wind acceleration and wave damping mechanisms. Our work will also help reveal what dominates the energy and momentum balances of the chromosphere, which are poorly understood. This will drastically improve our understanding of how the chromosphere impacts the magnetic field, which is crucial if we want to use SDO/HMI data to understand the coronal/heliospheric field.

Publications:

Performance YearReferenceInvestigation TypeActions
1McIntosh, Scott W.; De Pontieu, Bart; Tarbell, Theodo...
not set
1McIntosh, Scott W.; de Pontieu, Bart; Carlsson, Mats;...
not set

Presentations:

Performance YearReferenceActions
1de Pontieu, B.; Carlsson, M.; McIntosh, S.; Hansteen,...
1Vranjes, J.; Poedts, S.; Pandey, B. P.; de Pontieu,...
1De Pontieu, B.; Okamoto, T. J.; Rouppe van der Voor...

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