A statistical study of the spatial evolution of shock acceleration efficiency for 5 MeV protons and subsequent particle propagation

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

  • May Britt Kallenrode
Traveling interplanetary shocks can accelerate protons up to energies of some tens of MeV. Intensity and anisotropy time profiles observed in interplanetary space can be used to determine the scattering conditions as well as the evolution of the shock efficiency along the observer's magnetic field line. The latter can be described as a superposition of an azimuthal variation along the shock front, which accounts for the dependence of intensity time profiles on the angular distance between the observer and the nose of the shock, and a radial variation, which probably is related to the energetics of the solar event and the shock. Fits with a black box model to 44 particle events lead to the following results: (1) overall scattering conditions in interplanetary space are not different in events with and without interplanetary shock, (2) the radial variation S ∼ rα of the injection has a power law index α between -5.5 and +4.5 with α ≤ 0 for most of the events, (3) a separate solar component is required in four of 44 events only, (4) within the broad scatter from event to event, α and λ are independent of whether the observer is located east or west of the flare normal and (5) if the same shock has been observed by two spacecraft, observations on both spacecraft can be described consistently. Results (4) and (5) suggest that the description of the injection in the black box model is a reasonable approximation. The other results give hints on the acceleration: First, there appears to be no significant enhancement in overall interplanetary turbulence which could lead to a more efficient acceleration. Second, in most of the events presented here the number of injected particles per unit surface of the shock is highest close to the Sun; in about half of the events also the number of particles expressed as fraction of the ambient medium is highest close to the Sun. This has two implications: (1) either there is a strong contribution of flare-accelerated particles or, in the context of current knowledge more likely, the shock is a more efficient particle accelerator close to the Sun than in interplanetary space, and (2) the relatively small amount of particles accelerated locally in interplanetary space does not require significant acceleration, it might even be reaccelerated material from the large population of particles accelerated close to the Sun. Copyright 1997 by the American Geophysical Union.
Original languageEnglish
Article number97JA02035
JournalJournal of Geophysical Research A: Space Physics
Volume102
Issue numberA10
Pages (from-to)22335-22345
Number of pages11
ISSN0148-0227
DOIs
Publication statusPublished - 01.10.1997
Externally publishedYes

DOI

Recently viewed

Publications

  1. Grazing, exploring and networking for sustainability-oriented innovations in learning-action networks
  2. Training effects of two different unstable shoe constructions on postural control in static and dynamic testing situations
  3. »HOW TO MAKE YOUR OWN SAMPLES«
  4. Use of Machine-Learning Algorithms Based on Text, Audio and Video Data in the Prediction of Anxiety and Post-Traumatic Stress in General and Clinical Populations
  5. From "cracking the orthographic code" to "playing with language"
  6. Sliding Mode Control Strategies for Maglev Systems Based on Kalman Filtering
  7. Comparing temperature data sources for use in species distribution models
  8. Multiphase-field modeling of temperature-driven intermetallic compound evolution in an Al-Mg system for application to solid-state joining processes
  9. Comparison of Trajectory Estimation Methods Based on LIDAR and Monocular Camera in a Simulated Environment
  10. A Two-Stage Sliding-Mode High-Gain Observer to Reduce Uncertainties and Disturbances Effects for Sensorless Control in Automotive Applications
  11. Deeper Insights into Different Consumer Perceptions of CSR Communication
  12. The buffering effect of selection, optimization, and compensation strategy use on the relationship between problem solving demands and occupational well-being
  13. CubeQA—question answering on RDF data cubes
  14. Automating SPARQL Query Translations between DBpedia and Wikidata
  15. Beyond Structural Adjustment
  16. Mapping perceptions of energy transition pathways
  17. Biomedical Entity Linking with Triple-aware Pre-Training
  18. Analog, Digital, and the Cybernetic Illusion
  19. Developing a Process for the Analysis of User Journeys and the Prediction of Dropout in Digital Health Interventions:
  20. Ontology-based automatic classification for Web pages
  21. Vector Fields Autonomous Control for Assistive Mobile Robots
  22. Combined experimental-numerical analysis of the temperature evolution and distribution during friction surfacing
  23. Digital and IT-Enabled Organizational Transformation - Where Do We Go From Here?
  24. Exploring Management Control Systems for Biodiversity
  25. Model Predictive Control for Energy Optimization in Generators/Motors as Well as Converters and Inverters for Futuristic Integrated Power Networks
  26. Towards a global understanding of tree mortality
  27. Learning to collaborate while collaborating
  28. Nichtlineare Dynamik
  29. Temperature changes using excimer laser irradiation in a cochlear model
  30. Messung von Markenvorstellungen