ray shielding. A faster rotation rate increases the azimuthal winding, and consequently the strength, of the magnetic field in the super-Alfvénic “Parker spiral” regime. For this work, we adopt the model computed for a rotation period of $4$ days, mass $M_\star = 0.5 M_\odot$ and radius $R_\star = R_\odot$, consistent with observations [e.g. @Johns-Krull:07]. The model output comprised the steady-state magnetic field, together with the a complete description of the wind and its flow on a three-dimensional cartesian grid. The simulation box is taken to be a star-centered cube with volume $(48 R_{\star})^3$, which is sufficiently large to enclose the stellar “Alfvén surface” representing the point at which the wind becomes supersonic. The consequent simulation cell size is $0.36 R_\star$.

Energetic particles in the circum-T Tauri environment {#environ}
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Solar wind [*in-situ*]{} measurements generally exhibit an enhancement in the intensity of EPs corresponding to the passage of interplanetary shocks, with a broad variety of behavior such as enhancements delayed by a few hours, spikes, or no features at all [@Lario.etal:03]. Such measurements lead to the conclusion that shocks are efficient sources of accelerated particles. In the vicinity of T Tauri stars, intense flaring and eruptive activity is likely to produce 