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Science Investigation Goals and Instrument Requirements. Dr. George A. Doschek EIS US Principal Investigator Naval Research Laboratory Phone: 202-767-3527, FAX: 202-404-7997 e-mail: gdoschek@ssd5.nrl.navy.mil. Solar-B Spacecraft. Solar Photosphere at 5800 K. Solar Atmosphere at 10 5 K.
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Science Investigation Goals and Instrument Requirements Dr. George A. Doschek EIS US Principal Investigator Naval Research Laboratory Phone: 202-767-3527, FAX: 202-404-7997 e-mail: gdoschek@ssd5.nrl.navy.mil
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
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)
Simplified Schematic of EIS Sun Filter Primary Slit Grating CCD Long CCD Short
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)
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)