990901EIS_RR_Science.1 Science Investigation Goals and Instrument Requirements Dr. George A. Doschek EIS US Principal Investigator Naval Research Laboratory Phone: , FAX:

990901EIS_RR_Science.2 Solar-B Spacecraft

990901EIS_RR_Science.3 Solar Photosphere at 5800 K

990901EIS_RR_Science.4 Solar Atmosphere at 10 5 K

990901EIS_RR_Science.5 Solar Atmosphere at 10 6 K

990901EIS_RR_Science.6 Solar Atmosphere >10 6 K

990901EIS_RR_Science.7 Coronal Mass Ejection

990901EIS_RR_Science.8 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

990901EIS_RR_Science.9 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)

990901EIS_RR_Science.10 Simplified Schematic of EIS Sun Filter Grating Primary CCD Long CCD Short Slit

990901EIS_RR_Science.11 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 ( MK), Corona (1 - 3 MK), and Hot Portions of Solar Flares ( MK) –This Requires Observations in the Extreme Ultraviolet (EUV) –The Selected Wavelength Bands Are: Å and Å Instrument Alignment: EIS Images Are Required to Be Co-Aligned With Images From the Other Solar-B Instruments (Use He II 256 Å)

990901EIS_RR_Science.12 Fe XXIV Energy Levels

990901EIS_RR_Science.13 Short Wavelength Band

990901EIS_RR_Science.14 Long Wavelength Band

990901EIS_RR_Science.15 Long Wavelength Band for Different Solar Regions

990901EIS_RR_Science.16 Schematic Spectral Line Profiles

990901EIS_RR_Science.17 Explosive Event

990901EIS_RR_Science.18 Electron Density Sensitive Line Ratios

990901EIS_RR_Science.19 Electron Density Above a Polar Coronal Hole

990901EIS_RR_Science.20 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)