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Solar energetic particles and the solar cycle: Impact of solar magnetic field amplitude and geometry on solar particles diffusion coefficients

Barbara Perri - IAS; Sacha Brun - CEA, France; Antoine Strugarek - CEA, France; Victor Réville - IRAP, France

Session:  Interplanetary CMEs and Solar Particle Event


SEPs are correlated with the 11-year solar cycle due to their production by flares and interaction with the inner heliosphere: the solar magnetic field varies in amplitude but also in geometry, causing diffusion of the particles along and across the field lines; the solar wind distribution evolves, and its turbulence affects SEPs trajectories.

We combine 3D MHD compressible numerical simulations to compute the configuration of the magnetic field and the associated polytropic solar wind up to 1 AU, with analytical prescriptions of the corresponding parallel and perpendicular diffusion coefficients for SEPs. First, we analyze separately the impact of the magnetic field amplitude and geometry for a 100 MeV proton: by varying the amplitude, we change the amplitude of the diffusion by the same factor, and the radial gradients by changing the spread of the current sheet; by varying the geometry, we change the latitudinal gradients of diffusion by changing the position of the current sheets. Then, we use realistic solar configurations, showing that diffusion is highly non-axisymmetric due to the configuration of the current sheets, and that the distribution varies a lot with the distance to the Sun with a drift of the peak value.

Approaching deadlines:

Registration opens:

16 July 2020

Abstract submission opens:

16 July 2020

European Space Weather Medals:

6 September 2020

Registration deadline:

25 September 2020

Registration deadline: [extended]

10 October 2020

Abstract submission deadline:

4 September 2020