Center for Astrophysics Research and Technologies Seminar Series
Comparing Different Methods of Estimating Total Open Heliospheric Magnetic Flux
Presented by Samantha Wallace, UNM
There are extended periods over the solar cycle where significant discrepancies occur between the spacecraft observed total (unsigned) open magnetic flux and that determined from coronal models. In this paper, the total open heliospheric magnetic flux is computed using two different methods and then compared with results obtained using in situ interplanetary magnetic field observations. The first method involves using two different types of photospheric magnetic field maps as input to the Wang-Sheeley-Arge (WSA) model: (1) traditional Carrington or diachronic maps, and (2) Air Force Data Assimilative Photospheric Flux Transport (ADAPT) model synchronic maps. The second method uses observationally derived Helium and Extreme Ultraviolet (EUV) coronal hole maps overlain onto the same magnetic field maps in order to compute total open magnetic flux. The diachronic and synchronic maps are both constructed using magnetograms from the same source, namely the National Solar Observatory (NSO) Kitt Peak Vacuum Telescope (KPVT) and Vector Spectromagnetograph (VSM) magnetographs. The results of this work show that using observationally derived coronal holes to compute the total open flux agree remarkably well with that obtained from WSA, especially near solar minimum, This result suggests that, on average, the coronal models capture well the observed large scale coronal hole structure over most of the solar cycle. Both methods show significant deviations from the total unsigned flux as deduced from spacecraft data, especially near solar maximum, pointing to something other than poorly determined coronal area specification as the source producing these discrepancies.
2:00 pm, Thursday, March 10, 2016
PAIS-2540, PAIS
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