Cosmic rays in simulations of the solar wind

This webpage, hosted at the MEDOC data center, provides output data from MHD simulations performed using the Wind-Predict model (Réville et al. 2015, Perri et al. 2018), based on the PLUTO code (Mignone et al. 2007). They also include cosmic rays diffusion coefficients parallel and perpendicular to the magnetic field lines, computed using a Python post-processing pipeline.

Simulations

This data-set includes 5 simulations: 3 of them performed in 2.5D and 2 of them performed in 3D. All simulations correspond to a relaxed state of the wind for a given magnetic field configuration, there is hence no time evolution.

• The 2.5D simulations are theoretical studies of the influence of the magnetic field on the cosmic rays diffusion: the corona is set at 1.5 MK, and only the magnetic field parameters are changed.
  • Case D1 is a dipole of low amplitude (0.5 G at the surface at the equator).
  • Case Q1 is a quadrupole of low amplitude.
  • Case D10 is a dipole of strong amplitude (5 G at the surface at the equator).
• The 3D simulations are set using synoptic maps of a minimum of activity (October 1995) and a maximum of activity (August 1999), already published in another study (Réville & Brun 2017), and run up to 1 AU. Thus we provide 3D maps of the diffusion coefficient of cosmic rays in the inner heliosphere for realistic complex configurations.

The diffusion coefficients are computed using analytical formulae, from Zank et al. 1998 for the parallel diffusion, and from Shalchi et al. 2004 for the perpendicular diffusion. We have selected 7 rigidities for which we perform the computation, at 1, 10, 100, 445, 10³, 10⁴ and 10⁵ MV, ranging thus from SEPs to GCRs.

More details can be found in Perri et al. (2020), JSWSC, Topical issue "Space climate: The past and future of solar activity".

Data format

The data are provided using a VTK format, readable by visualization tools such as VisIt or Paraview, or programming language using the appropriate libraries. Here is a list of the physical quantities provided for each run, and the correspondance with the name used in the files:

• Radius grid: r
• Co-latitude grid: theta
• Longitude grid: phi
• Spherical wind velocity: vr, vt, and vp (assembled in vector V_sph)
• Cartesian wind velocity: vx, vy, and vz (assembled in vector V_cart)
• Spherical magnetic field: br, bt, and bp (assembled in vector B_sph)
• Cartesian magnetic field: bx, by, and bz (assembled in vector B_cart)
• Density: rho
• Pressure: prs
• Parallel diffusion coefficient for various rigidities (indicated in Volts): lpar_1e6, lpar_1e7, lpar_1e8, lpar_4e8, lpar_1e9, lpar_1e10, lpar_1e11
• Perpendicular diffusion coefficient for various rigidities: lperp_1e6, lperp_1e7, lperp_1e8, lperp_4e8, lperp_1e9, lperp_1e10, lperp_1e11

---

HTML generation date: 2021-12-17T12:12:21.695246