Reconstructing Coronal Hole Areas With EUHFORIA and Adapted WSA Model: Optimizing the Model Parameters. Issue 11 (26th November 2019)

• Record Type: Journal Article
• Authors: Asvestari, E.; Heinemann, S. G.; Temmer, M.; Pomoell, J.; Kilpua, E.; Magdalenic, J.; Poedts, S.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 11(2019)
• Page Start: 8280
• Page End: 8297
• Publication Date: 2019-11-26
• Subjects: coronal holes -- PFSS -- EUHFORIA; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA027173
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: The adopted Wang‐Sheeley‐Arge (WSA) model embedded in EUHFORIA (EUropean Heliospheric FORecasting Information Asset) is compared to EUV observations. According to the standard paradigm, coronal holes are sources of open flux; thus, we use remote sensing EUV observations and CATCH (Collection of Analysis Tools for Coronal Holes) to extract CH areas and compare them to the open flux areas modeled by EUHFORIA. From the adopted WSA model we employ only the Potential Field Source Surface (PFSS) model for the inner corona and the Schatten Current Sheet (SCS) model for the outer (PFSS+SCS). The height, R ss, of the outer boundary of the PFSS, known as the source surface, and the height, R i, of the inner boundary of the SCS are important parameters affecting the modeled CH areas. We investigate the impact the two model parameters can have in the modeled results. We vary R ss within the interval [1.4, 3.2] R ⊙ with a step of 0.1 R ⊙, and R i within the interval [1.3, 2.8] R ⊙ with the same step, and the condition that R i < R ss . This way we have a set of 184 initial parameters to the model, and we assess the model results for all these possible height pairs. We conclude that the default heights used so far fail in modeling accurately CH areas and lower heights need to be considered. Key Points: We assess the capability of the PFSS+SCS models adopted by EUHFORIA in reconstructing CH areas The heights of the source surface and the inner boundary of the SCS model impact the results Lower values for these two heights improved the results