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| Titel |
A Direct Approach to Determine the Perpendicular Mean Free Path of Solar Energetic Particles in a Turbulent and Spatially Varying Magnetic Field |
| VerfasserIn |
Hongqing He, Weixing Wan |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081110
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| Zusammenfassung |
| A direct approach to explicitly determine the perpendicular mean free path of solar energetic
particles (SEPs) with the influences of parallel diffusion and composite dynamical turbulence
in a spatially varying magnetic field is presented. As theoretical applications of the direct
approach, we investigate the inherent relations between the perpendicular mean free
path and various parameters concerning physical properties of SEPs as well as
those of interplanetary conditions such as solar wind and the turbulent magnetic
field. Comparisons of the perpendicular mean free paths with and without adiabatic
focusing are also presented. The direct method shows encouraging agreement with
spacecraft observations, suggesting it is a reliable and useful tool in theoretical
investigations and space weather forecasting. In the typical parameter regimes,
λ-¥(r) - r0.29 and λ-¥(r)-λ-¥(r) - r-0.58 in the inner heliosphere; λ-¥(r) - r0.11 and
λ-¥(r)-λ-¥(r) - r-0.22 in the outer heliosphere. Generally, the ratio λ-¥-λ-¥ is in the range
0.01 - 0.20. However, when the turbulence strength δB-B is sufficiently large, the
ratio λ-¥-λ-¥ would approach or exceed unity. The critical value of the turbulence
strength δB-B for 100 MeV protons is about 2.34, beyond which the perpendicular
mean free path λ-¥ becomes increasingly larger than the parallel mean free path λ-¥. |
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