Both the model and PSP data indicate that the radial velocity fluctuates mainly between 300 and 400 km s−1, except for two high-speed streams above 500 km s−1 at DOY 309 and 322 in the model and DOY 313 and 319 in the SWEAP data. The model suggests that the solar wind streams sampled by PSP during this time were primarily connected with two equatorial coronal holes of opposite magnetic polarity. PFSS Model. FIELDS measures the electric and magnetic fields and waves, Poynting flux, absolute plasma density and electron temperature, spacecraft floating potential and density fluctuations, and radio emissions (Bale et al. The estimates for PSP’s first closest perihelion, occurring in 2024 at Exospheric Solar Wind CCMC Services available for Exospheric Solar Wind Request a Run View Request Results. A 3D model of Ceres, a dwarf planet in the main asteroid belt between Mars and Jupiter. Credit: NASA Visualization Technology Applications and Development (VTAD) › Download Options In Depth: Parker Solar Probe. AFRL/Space Vehicles Directorate, Kirtland AFB, Albuquerque, NM 87117, USA, 5 Methods: The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. Authors: M. S. Venzmer, V. Bothmer (Submitted on 20 Nov 2017) Abstract: The scope of this study is to model the solar-wind environment for the Parker Solar Probe's unprecedented distances down to 9.86 Rs in its mission phase during 2018-2025. The model suggests that PSP remains in the negative sector below the heliospheric current sheet throughout the entire period as the radial field steadily increases in strength from −20 nT at 0.348 au to −76 nT at 0.166 au and then back to −20 nT at the end of the time window. Need Eqn. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Using the time sequence of magnetic field and solar wind velocity, density, and temperature for 2018 August 1 20:00:00 UT–2019 August 13 20:00:00 UT derived from the WSA model as inner boundary conditions, we solve the ideal MHD equations on a nonuniform 200 × 256 × 128 (r, , θ) spherical grid (e.g., Δr ≈ 0.645, 1.08, and 1.72 Rs at r = 0.1, 0.5 and 1.0 au, respectively), with the specific heat ratio γ set to 1.5. However, there is a considerable discrepancy around 2018.65 when a coronal mass ejection (CME) arrived at Earth and caused a strong geomagnetic storm. Parker's spiral magnetic field was divided in two by a current sheet, a mathematical model first developed in the early 1970s by Schatten. These results are mostly consistent with the PSP FIELDS and SWEAP data, excluding comparison at distances much larger than 0.25 au since the SWEAP measurements are frequently made at low signal-to-noise ratios beyond that distance and thus may contain artifacts. Those times are marked by the presence of a number of Earth-facing equatorial coronal holes and northward extensions of the southern polar coronal hole, and it is possible that some of these features may not have been reproduced accurately by the WSA model. in contrast to the first PSP orbit when the opposite was observed. We note that magnetograph observations from different instruments can vary by up to a factor of 2 (Riley 2007). 3,000,000 km) from the photosphere (surface); but the transition (or "sonic point") now appears to be much lower, perhaps only one solar radius (approx. Select your desired journals and corridors below. This makes sense because Earth was mostly above/below the equatorial plane during PSP's first/second orbit. We compare the numerical results of our model with Parker Solar Probe measurements of the fast solar wind flow and find good agreement between them. Model Developer(s) H.Lamy, V.Pierrard IASB-BIRA. T. K. Kim1, N. V. Pogorelov2, C. N. Arge3, C. J. Henney4, S. I. Jones-Mecholsky3,5, W. P. Smith6, S. D. Bale7,8,9, J. W. Bonnell10, T. Dudok de Wit11, K. Goetz12, P. R. Harvey13, R. J. MacDowall14, D. M. Malaspina15, M. Pulupa13, J. C. Kasper16,17, K. E. Korreck17, M. Stevens17, A. W. Case17, P. Whittlesey18, R. Livi18, D. E. Larson18, K. G. Klein19, and G. P. Zank2, Published 2020 February 3 • Outer Coronal. We further estimate the solar wind density and temperature at the MS-FLUKSS inner boundary based on the assumptions of constant momentum flux and thermal pressure balance, respectively (see Linker et al. It appears that, in the model, PSP may have grazed this stream 3–4 days too early and thus crossed the heliospheric current sheet 3–4 days prematurely as well.