Accession Number : AD1020868


Title :   Photospheric Driving of Non-Potential Coronal Magnetic Field Simulations


Descriptive Note : Technical Report,15 Sep 2014,14 Sep 2017


Corporate Author : University of Durham Durham United Kingdom


Personal Author(s) : Yeates,Anthony


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1020868.pdf


Report Date : 19 Sep 2016


Pagination or Media Count : 19


Abstract : The objective of this research is to develop a new photospheric driver to assimilate radial magnetic maps into magneto-frictional (MF) simulations of the Suns coronal magnetic field. Together with the Air Force Data Assimilative Photospheric Flux Transport (ADAPT) Model to assess how the MF model can improve background solar wind forecasts and whether flux ropes in the model can constrain magnetic topology or interplanetary magnetic fields. In the second year of the project improved filtering of magnetic maps was developed to reduce spurious electric fields. A new technique was developed for sparse reconstruction of electric field based on L1-minimization, which allowed a study of the effect of flux imbalance in magnetic maps. The PI and his associates published a description/proof-of-concept of the new MF driving technique, with test cases taken from (a) a simple flux transport model (with known electric field) and (b) a two-month ADAPT sequence. A comparison of different magnetic maps and coronal models was begun in collaboration with Predictive Science, Inc. This study focuses on how the differences affect solar wind predictions. The new MF code was used to assess potential benefits of placing a magnetograph at the L5 Lagrange point. This research developed the concept of field line helicity for robust identification of flux ropes in the corona. The results of these two studies has been published. Software was developed to automatically detect flux ropes using field line helicity, and tested on a previous MF model.


Descriptors :   magnetic fields , solar corona , solar wind , electric fields


Distribution Statement : APPROVED FOR PUBLIC RELEASE