SCIENCE GOALS AND OBJECTIVES: THE GOALS OF THIS PROPOSAL ARE TO CAPITALIZE ON THE UNIQUE PROPERTIES OF VISIBLE LINE SPECTROSCOPY TO FULLY EXPLOIT THE UNIQUE OBSERVING CONDITIONS PROVIDED BY THE CONSIDERABLE DIMMING OF THE SKY BRIGHTNESS DURING THE TOTAL SOLAR ECLIPSE OF 21 AUGUST 2017 TO EXPLORE THE PHYSICAL PROPERTIES OF (1) THE CORONAL PLASMA (2) THE SOLAR WIND AS IT EXPANDS INTO INTERPLANETARY SPACE AND (3) CORONAL MASS EJECTIONS AS THEY ORIGINATE AND ACCELERATE. THE OBJECTIVES ARE TO (1) DESIGN AND BUILD TWO NEW TRIPLE-CHANNEL IMAGING SPECTROGRAPHS (2) ACQUIRE THE LINE PROFILE AND INTENSITY OF SEVERAL KEY CORONAL EMISSION LINES IN THE VISIBLE WAVELENGTH RANGE (3) OPERATE THE TWO SPECTROGRAPHS SIMULTANEOUSLY DURING THE ECLIPSE TO IMAGE THESE SPECTRAL LINES OVER A CORONAL AREA OF 5X8 SQUARE SOLAR RADII.INSTRUMENT AND DATA ACQUISITION: A NOVEL DESIGN OF A DUAL-CHANNEL IMAGING SPECTROGRAPH WAS BUILT AND OPERATED DURING THE 20 MARCH 2015 ECLIPSE. THE OBSERVING SEQUENCE OF THIS SCANNING SPECTROGRAPH ENABLED THE ACQUISITION OF FE XI 789.2 AND FE XIV 530.3 NM SPECTRAL LINE INTENSITIES PROFILES AND DOPPLER SHIFTS (WHEN PRESENT) OVER AN AREA OF 2.5X8 SQUARE SOLAR RADII. THESE DATA LED TO THE SERENDIPITOUS DETECTION OF A CME FRONT WITH SECTIONS TRAVELING AWAY FROM THE OBSERVER AT SPEEDS RANGING FROM 100 TO 1500 KM/S. FURTHERMORE THEY LED TO THE ASTOUNDING DISCOVERY OF EMISSION FROM NEUTRAL OR SINGLY STATES OF ELEMENTS IN PLASMOIDS EMBEDDED IN THE CME FRONT CHARACTERISTIC OF COOL PROMINENCE MATERIAL EJECTED WITH THE CME RETAINING ITS ORIGINAL PROPERTIES. TO ACHIEVE THE PROPOSED OBJECTIVES WE WILL USE THE UNIQUE FEATURES OF THE DUAL-CHANNEL SPECTROGRAPH TO BUILD TWO NEW TRIPLE-CHANNEL SPECTROGRAPHS. THE MAIN FEATURES OF THE NEW DESIGN OF EACH SPECTROMETER ARE AS FOLLOWS: (1) AN 8 SOLAR RADII LONG SLIT (2) THREE WAVELENGTH BANDS CENTERED ON THE FE X 637.4 FE XI 789.2 AND FE XIV 530.3 FORBIDDEN LINES AND (3) EACH 50 NM WIDE BAND IS DESIGNED TO INCLUDE OTHER SPECTRAL LINES CHARACTERISTIC OF HOT AND COOL (CHROMOSPHERIC) EMISSION. BY OPERATING THE TWO SIMULTANEOUSLY DURING THE ECLIPSE AN UNPRECEDENTED CORONAL AREA OF 5X8 SQUARE SOLAR RADII WILL BE SCANNED WITHIN THE APPROXIMATE 2 MINUTES DURATION OF THE 2017 ECLIPSE AT ANY GIVEN LOCATION ALONG THE PATH OF TOTALITY.DATA ANALYSIS METHODOLOGY: THESE NEW DATA INCLUDING SPECTRAL LINE INTENSITIES PROFILES AND DOPPLER SHIFTS OF KEY CORONAL (AND CHROMOSPHERIC) EMISSION LINES WILL ENCOMPASS THE CRITICAL REGIONS OF CORONAL HEATING SOLAR WIND ACCELERATION AND CME PROPAGATION. WHILE RETAINING THE SAME DIAGNOSTIC POTENTIAL OF ANY EUV LINE FROM THE SAME ION FORBIDDEN CORONAL LINES IN THE VISIBLE WAVELENGTH RANGE CAN BE OBSERVED AT FAR LARGER HEIGHTS THAN THEIR EUV COUNTERPARTS. THIS PROPERTY WILL ENABLE THE APPLICATION OF EMISSION LINE SPECTROSCOPY TO REGIONS SELDOM OR NEVER REACHED BY PREVIOUS INSTRUMENTATION. STANDARD DIAGNOSTIC TECHNIQUES DESCRIBED IN LANDI ET AL. (2016) WILL BE APPLIED TO THESE DATA TO DETERMINE: (1) THE ELECTRON TEMPERATURE DISTRIBUTION IN THE CORONA (2) THE EMPIRICAL IDENTIFICATION OF THE SOLAR WIND FREEZE-IN DISTANCE (3) THE COMPOSITION OF THE CORONAL PLASMA INCLUDING EMISSION CHARACTERISTIC OF NEUTRALS AND SINGLY IONIZED ELEMENTS (4) IONIC TEMPERATURES OF SELECT ELEMENTS (5) THE PRESENCE OF WAVE MOTIONS THROUGH THE NONTHERMAL BROADENING OF LINE PROFILES AND (6) THE THERMAL STRUCTURE AND DYNAMICS OF CME PLASMAS.RELEVANCE: THE DATA TO BE ACQUIRED WITH THE TRIPLE-CHANNEL SPECTROGRAPHS WILL COMPLEMENT DATA FROM THE DIFFERENT NASA SPACE-BASED OBSERVATORIES OPERATING AT THAT TIME. THE PROPOSED INSTRUMENT AND DATA WILL DIRECTLY ADDRESS OBJECTIVE 1.4 FROM THE NASA STRATEGIC PLAN TO "UNDERSTAND THE SUN AND ITS INTERACTIONS WITH EARTH AND THE SOLAR SYSTEM INCLUDING SPACE WEATHER".