English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Photospheric electric fields, estimated from sequences of vector magneticfield and Doppler measurements, can be used to estimate the flux of magneticenergy (the Poynting flux) into the corona and as time-dependent boundaryconditions for dynamic models of the coronal magnetic field. We have modifiedand extended an existing method to estimate photospheric electric fields thatcombines a poloidal-toroidal (PTD) decomposition of the evolving magnetic fieldvector with Doppler and horizontal plasma velocities. Our current, morecomprehensive method, which we dub the "{\bf P}TD-{\bf D}oppler-{\bf F}LCT {\bfI}deal" (PDFI) technique, can now incorporate Doppler velocities fromnon-normal viewing angles. It uses the \texttt{FISHPACK} software package tosolve several two-dimensional Poisson equations, a faster and more robustapproach than our previous implementations. Here, we describe systematic,quantitative tests of the accuracy and robustness of the PDFI technique usingsynthetic data from anelastic MHD (\texttt{ANMHD}) simulations, which have beenused in similar tests in the past. We find that the PDFI method has less than$1%$ error in the total Poynting flux and a $10%$ error in the helicity fluxrate at a normal viewing angle $(\theta=0$) and less than $25%$ and $10%$errors respectively at large viewing angles ($\theta<60^\circ$). We compare ourresults with other inversion methods at zero viewing angle, and find that ourmethod's estimates of the fluxes of magnetic energy and helicity are comparableto or more accurate than other methods. We also discuss the limitations of thePDFI method and its uncertainties.

A Comprehensive Method of Estimating Electric Fields from Vector Magnetic Field and Doppler Measurements