Observation and Analysis of Fe XVIII Solar X-Ray Emission.

Abstract

X-ray spectra from the solar corona, obtained with a crystal spectrometer on the OV1-17 satellite, are used to analyze Fe XVIII emission lines between about 14 and about 16A. The first comprehensive and accurate determinations of the coronal Fe XVIII wavelengths and relative intensities are made for the 2p-3d and 2p-3s transitions. Eighteen emission lines or line blends of Fe XVIII were observed and analyzed, including all X-ray lines previously observed in hot laboratory plasmas in this wavelength region. The measured OV1-17 wavelengths are in excellent agreement with the best laboratory measurements. The relative intensities for the Fe XVIII lines are used to deduce relative effective collision strengths for a number of transitions. The potential effects of cascades, to the 2s22p43d, 3p and 3s levels of Fe XVIII, on the interpretation of these relative collision strengths are discussed in detail. Calculations of the relative collision strengths using the modified Bethe approximation are compared to the OV1-17 deduced values.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1977
Accession Number
ADA045114

Entities

People

  • A. B. C. Walker Jr.
  • Hugo R. Rugge

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Accuracy
  • Air Force
  • Electrons
  • Energy
  • Energy Levels
  • Equations
  • Ground Level
  • Ground State
  • Ionization
  • Measurement
  • Radiation
  • Solar Corona
  • Solar X Rays
  • Space Sciences
  • Two Dimensional
  • X Ray Spectra
  • X Rays

Fields of Study

  • Physics

Readers

  • Solar Physics

Technology Areas

  • Space
  • Space - Orbital Debris