DOI: 10.5281/zenodo.17217944
title: The UAH Predictions of the Solar Wind and Magnetic Field at the Parker Solar Probe during Solar Encounter 25 (2025-09-18)

description: 1. Model

The MS-FLUKSS heliospheric MHD model is coupled with the WSA model (Kim et al. 2020), which used ADAPT-GONG input magnetograms, with the PFSS source surface height and the WSA outer boundary at 2.5 and 21.5 solar radii, respectively. The MHD model propagates the solar wind from 21.5 solar radii to 236 solar radii (1.1 AU) to fully enclose the PSP trajectory. Hence, field line tracing from PSP to the solar surface is performed through the MHD domain down to 21.5 solar radii instantaneously at approximately 1 hour cadence, where the origin of the field line on the photosphere is already known in the WSA model. See Badman et al. (2023) for details.

MS-FLUKSS: Multi-Scale Fluid-Kinetic Simulation Suite

MHD: Magnetohydrodynamic

WSA: Wang-Sheeley-Arge

ADAPT: Air Force Data Assimilative Photospheric flux Transport

GONG: Global Oscillation Network Group

PFSS: Potential Field Source Surface

PSP: Parker Solar Probe

 

2. Data

There are two sets of data files as described below:

(A) "PSP_AGONG_1_R000.dat" - "PSP_AGONG_1_R011.dat" and "PSP_AGONG_2_R000.dat" - "PSP_AGONG_2_R011.dat": MS-FLUKSS simulation results extracted along the PSP trajectory labeled by the input magnetogram (two independent sets of 12 realizations of ADAPT-GONG each) for the WSA model. 

Each data file consist of a header and 16 columns of numerical values in the following order:

(1) Time (fractional year)

(2) Heliocentric distance (AU)

(3) MS-FLUKSS longitude (rotated by ~180 degrees from inertial heliographic longitude in degrees)

(4) MS-FLUKSS latitude (same as heliographic latitude in degrees)

(5) Solar wind proton number density (cm^-3)

(6) Solar wind Vr (km/s)

(7) Solar wind Vphi (km/s)

(8) Solar wind Vtheta (km/s)

(9) Thermal pressure of solar wind and interstellar pickup ion mixture (picodyne/cm^2)

(10) Br (microgauss)

(11) Bphi (microgauss)

(12) Btheta (microgauss)

(13) Level set value for tracking the heliospheric current sheet

(14) Level set value for tracking the initial MS-FLUKSS longitude at the inner boundary

(15) Level set value for tracking the initial MS-FLUKSS latitude at the inner boundary

(16) Solar wind temperature.

 

(B) "UAH_psp_e25_20250918*_agongWSAmhd.csv": Carrington longitude and latitude of the predicted magnetic footpoint from 2025-09-18 to 2025-09-30.

 

Each data file consists of 4 columns of numeric values in the following order:

(1) Date (YYYY-MM-DD)

(2) Time (hh:mm:ss in UT)

(3) Carrington longitude (degree)

(4) Carrington latitude (degree)

 

Note that the tracking values in the original MHD simulation data files contain an interpolation error across 0 (360) degree longitude, so we manually corrected the error in the footpoint coordinates files.

 

3. Figures

There is one figure showing plots of predicted Br, Vr, density, and temperature at PSP: uah_psp_e25_20250918_agongWSAmhd.pdf.

A plot showing the footpoint prediction results projected onto the solar disk is available at the PSP science gateway, at https://psp-gateway.jhuapl.edu/website/SciencePlanning/MissionEvents/, under “Encounter 25”.