报告题目：Solar Energetic Particle Acceleration and Transport in the Inner Heliosphere
报告人：赵璐璐 博士 （Florida Institute of Technology）
报告摘要：The acceleration and transport of solar energetic particles in the inner heliosphere is a long-standing problem in both space physics and astrophysics. Typical theories of acceleration mechanisms include stochastic acceleration by resonating with cascading magnetohydro- dynamic waves in solar flares or diffusive shock acceleration in the coronal mass ejection (CME) or co-rotating interaction region (CIR). In the vicinity of the shock driven by a CME, particles can be accelerated through the first-order Fermi acceleration, yielding a power-law energy spectrum. The power-law index is fully determined by shock properties and is independent of species. However, in many large SEP events, rather than exhibiting a single power law, the event-integrated spectra indices were distinct in different species. The event-integrated spectra can be described either by a power law with exponential rollover or by a double power law. The origins of the spectral breaks were suggested as either in the acceleration site or in the interplanetary transport process. In the acceleration site, finite shock lifetime, finite shock size, and shock geometry are considered as probable causes for the spectral break. On the other hand, in the interplanetary transport process, energetic particle spectra are also modulated by the energy-dependent diffusion processes. Investigation on the origins of the spectral break serve as a probe into both the acceleration and transport processes.