Space Weather and the Radiation Environment

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Space Weather and the Radiation Environment
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Overview

• Types of Radiation
• Units of Energy
• Electromagnetic Radiation
• Particle Radiation
• Sources of Radiation in Space
• The Solar Wind
• Galactic Cosmic Radiation
• Solar Flares and Coronal Mass Ejections
• Radiation Risk Assessment and Mitigation

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Types of Radiation
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Electron Volts

• 1 eV is the amount of energy required to move an
  electron across a 1 Volt electric potential.
• Visible light has energies on the order of 1eV.
• UV light of 10eV or more is enough to burn skin.
• Gamma Rays carry energies on the order of 1012 eV
• Particle energies are usually described by
  electron volts per nucleon

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Electromagnetic Radiation
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Particle Radiation
?
HZE
Neutrons
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Sources of Radiation in Space
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The Solar Wind
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Galactic Cosmic Radiation
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Solar Flares
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Coronal Mass Ejections (CMEs)
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Solar Energetic Particles
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Radiation Risk Assessment and Mitigation
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How do We Know What is Really Dangerous?

• Radiation dose exposure limits compared to
  terrestrial exposures for radiation workers
• Astronauts use As Low As Reasonably Achievable
  (ALARA) criteria
• Typical radiation exposures in space fall well
  below dose limits
• So, why do we care?

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What Factors Influence Whether a Given Class of
Radiation is Dangerous?

• Type of radiation and energy spectrum
• Quality Factors
• Linear Energy Transfer and Penetration Depth
  (Bragg Peak)
• Spallation
• Flux/Fluence
• Type of shielding

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How Can We Avoid Harmful Space Radiation?

• Mission Planning
• Space Weather Forecasting
• Shielding
• There May Be Nothing We Can Do

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• Things to Remember
• Electron Volts
• Types of Radiation
• Relative Dangers of Each Type of Radiation
• Sources of Space Radiation
• General Features of Space Radiation Sources
• Radiation Risk Assessment and Mitigation