Pergamon www.elsevier.com/locate/asr doi: lO.l016/SO273-1177(03)00932-3 Available online at www.sciencedirect.com SCIENCE DIRECT* SHOCK ACCELERATION OF ENERGETIC PARTICLES IN WAVE HEATED CORONA T. Laitinen’, R. Vainio2 ‘Space Research Laboratory, VISPA and Department of Physics, FIN-20014 University of Turku, Finland 2Department of Physical Sciences, PO. Box 64, FIN-00014 University of Helsinki, Finland ABSTRACT The solar wind wave heating models require substantial amount of wave power in order to efficiently heat and acceler- ate solar wind. The level of fluctuations is however limited by energetic particle observations. The simplest cyclotron sweep models result in convection-dominated transport, contradicting observations. However, models incorporating wave-wave -interactions, which cause wave energy to cascade in wavenumber, allow more reasonable energetic parti- cle transport in the interplanetary space. The mean free path of the energetic particles remains still relatively short in the corona, providing favorable conditions for coronal mass ejection (CME) related shock acceleration. We study the consequences of this scenario on the energetic particle production related to CMEs. The role of self-generated waves is also discussed. 0 2003 COSPAR. Published by Elsevier Ltd. All rights reserved. INTRODUCTION Coronal mass ejections (CMEs) are long since believed to be related with energetic particle acceleration near the Sun. Observations suggest that CME driven shocks are capable of accelerating ions to tens of MeV/n as they travel through corona and interplanetary space (Cane et al., 1988). The role of flares and CMEs as accelerators is a subject of continuous discussion. Although CME accelerated particle modeling has been around for several decades, one crucial observational detail is still missing: the coronal transport properties of the energetic particles, which determine the acceleration efficiency of the shock, are still unknown. The wave power and composition of particle-scattering plasma waves may greatly influence our understanding on the capabilities of shock as particle energizer. Recently, Vainio and Laitinen (2001) commenced a study relating the requirements of a wave-related solar wind heating model, the cyclotron sweep model (Tu and Marsch, 1997), to energetic particle transport and acceleration. They found that the required wave power exceeded the power allowed by energetic particle observations by several orders of magnitude. However, while the obtained interplanetary transport contradicts observations, the coronal values allow efficient shock acceleration (Laitinen et al., 2002). The cyclotron sweep model, however, is not consistent with the observed interplanetary plasma turbulence, which suggests that the wave power is cascaded to higher frequencies by nonlinear wave-wave interactions (e.g., Marsch, 1991). The cascading reduces significantly the scattering power, thus allowing a more reasonable interplanetary transport. However, this will also affect the acceleration efficiency of the coronal shock. In this study we take the first step into incorporating cascading into the coronal acceleration modeling by applying cascade to the wave spectrum required by effective cyclotron heating. We present simulation results of energetic particle acceleration by parallel and oblique shock waves. In addition, we discuss the implications of cascading to the waves generated by the energetic particles themselves, which have been suggested to play an important role in large energetic particle events (Ng and Reames, 1994; Ng et al., 1999). Adv. Space Res. Vol. 32, No. 12, pp. 2603-2608.2003 0 2003 COSPAR. Published by Elsevier Ltd. All rights reserved Printed in Great Britain 0273-l 177/$30.00 + 0.00