Science Investigation Goals and Instrument Requirements

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Science Investigation Goals and Instrument
Requirements

• Dr. George A. Doschek
• EIS US Principal Investigator
• Naval Research Laboratory
• Phone [phone], FAX [phone]
• e-mail gdoschek_at_ssd5.nrl.navy.mil

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Solar-B Spacecraft
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Solar Photosphere at 5800 K
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Solar Atmosphere at 105 K
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Solar Atmosphere at 106 K
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Solar Atmosphere gt106 K
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Coronal Mass Ejection
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Extreme-Ultraviolet Imaging Spectrometer (EIS)

• EIS Records Solar Extreme-Ultraviolet (EUV)
  Spectra That Contain Information on the Dynamics,
  Velocity, Temperature, and Density of the
  Emitting Plasma
• Spectra Are Obtained With High Spatial Resolution
• Spectra at Many Locations Within an Entire Solar
  Structure Can Be Recorded
• Spectra Are Obtained With Sufficient Time
  Resolution to Determine the Dynamics As a
  Function of Position Within Solar Flare and
  Active Region Loops
• Spectra Can Be Accurately Related to the Images
  Obtained From the Solar-B White Light and X-Ray
  Telescopes
• EIS Is the First EUV Solar Spectrometer Capable
  of Obtaining High Spectral Resolution Data With
  Both High Spatial and Temporal Resolution

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EIS Science Objectives

• Determine the Physical Mechanism(s) Responsible
  for Coronal Heating in the Quiet Sun and Active
  Regions (Detect Magnetic Reconnection, Wave
  Heating, Etc.)
• Determine the Physical Mechanism(s) Responsible
  for Transient Phenomena in the Solar Atmosphere
  Explosive Events, Eruptive Prominences, Coronal
  Mass Ejections, Solar Flares (Determine Energy
  Transport and Mass Motions in Different
  Atmospheric Regions During Transient Events)
• Determine the Relationship of Coronal Phenomena
  to the Dynamics of Photospheric Magnetic Fields
  (Relate EIS Observations to Data Obtained by the
  Solar-B White Light and X-Ray Telescopes)

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Simplified Schematic of EIS
Sun
Filter
Primary
Slit
Grating
CCD Long
CCD Short
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EIS Instrument Requirements for Satisfying the
Science Objectives

• Spatial Resolution EIS Is Required to Resolve
  Solar Structures Equal to or Less Than 1400 km In
  Size (2 Arcsec)
• Spectral Resolution EIS Is Required to Determine
  Spectral Line Wavelengths to an Accuracy of About
  3 km/s, and Is Required to Measure Nonthermal
  Motions As Small As 20 km/s From Line Widths
• Temporal Resolution EIS Is Required to Obtain
  Accurate Measurements of Strong Line Intensities
  and Line Widths Every 3 s in Highly Dynamic
  Events Such As Flares, and As Rapidly As Every 10
  s in Less Dynamic Phenomena Such As Active Region
  Loops
• Temperature Coverage EIS Is Required to Obtain
  Imaging/Spectral Measurements From Spectral Lines
  Emitted in the Transition Region (0.1 - 1 MK),
  Corona (1 - 3 MK), and Hot Portions of Solar
  Flares (6 - 20 MK)
• This Requires Observations in the Extreme
  Ultraviolet (EUV)
• The Selected Wavelength Bands Are 180 - 204 Å
  and 250 - 290 Å
• Instrument Alignment EIS Images Are Required to
  Be Co-Aligned With Images From the Other Solar-B
  Instruments (Use He II 256 Å)

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Fe XXIV Energy Levels
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Short Wavelength Band
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Long Wavelength Band
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Long Wavelength Band for Different Solar Regions
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Schematic Spectral Line Profiles
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Explosive Event
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Electron Density Sensitive Line Ratios
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Electron Density Above a Polar Coronal Hole
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The EIS Subsystems Provided By NASA

• An Articulated Multi-Layer Coated Telescope
  Mirror
• A Multi-Layer Coated Grating With Focussing
  Capability
• A Thin Aluminum Entrance Filter and Mount
• A Post Slit Thin Aluminum Filter and Mount
• A Slit Assembly Mechanism (Interchangeable Slits
  and a Shutter)