---
abstract: 'On 2000 April 4-6 the Energetic and Relativistic Nuclei and Electron particle
  telescope on the Solar and Heliospheric Observatory spacecraft observed a major
  solar energetic particle (SEP) event associated with two coronal mass ejections
  (CMEs) separated by approximately 8 hr. The first CME was accompanied by a low-
  frequency type II radio burst observed by the WAVES receivers on the Wind spacecraft.
  Analysis of the high-precision measurements of the \raisebox-0.5ex\textasciitilde20
  MeV proton flux anisotropy, model fitting of the type II dynamic spectrum, and SEP
  transport modeling support the idea that the shock wave of the first CME was an
  efficient accelerator for \raisebox-0.5ex\textasciitilde20 MeV protons during
  only the first 6 hr after the launch. This shock gradually slowed down, weakened,
  and became transparent for the protons produced by the second eruption behind the
  previous CME. The main production of SEPs due to the two successive eruptions continued
  together for 12 hr. The near-Earth SEP event was additionally amplified by the SEP
  mirroring in the interplanetary magnetic field draping at the edge of an old CME
  beyond the Earth''s orbit, which made the SEP intensity-time profiles more prolonged
  than would be expected based on the assumption of SEP transport in the standard
  solar wind.'
adsnote: Provided by the SAO/NASA Astrophysics Data System
adsurl: https://ui.adsabs.harvard.edu/abs/2009ApJ...700L..51K
authors:
- L. Kocharov
- T. Laitinen
- A. Al-Sawad
- O. Saloniemi
- E. Valtonen
- M. J. Reiner
category: publications
date: '2009-07-01'
doi: 10.1088/0004-637X/700/1/L51
draft: false
featured: false
journal: ApJl
month: July
number: '1'
pages: L51-L55
projects: []
publication: ApJl
publication_types:
- '2'
tags:
- Acceleration of particles
- Shock waves
- 'Sun: particle emission'
title: 'Gradual Solar Energetic Particle Event Associated with a Decelerating Shock
  Wave'
type: ARTICLE
volume: '700'
year: '2009'
---