THE PLASMA DISTRIBUTION IN THE IO TORUS DURING THE JUNO EPOCH. THE PROPOSED INVESTIGATION AIMS TO MEASURE THE PLASMA DISTRIBUTION IN THE IO TORUS DURING THE JUNO EPOCH MAP ITS DENSITY AND TEMPERATURE STRUCTURE AS A FUNCTION OF GEOMETRY RELATIVE TO JUPITER AND IO AND USE THE RESULTS TO TEST PREDICTIONS FOR HOW PLASMA BEHAVES IN JUPITER'S DYNAMIC MAGNETOSPHERE. THE TORUS IS A PROMINENT FEATURE OF JUPITER'S MAGNETOSPHERE. NEARLY ALL OF THE PLASMA IN THIS VAST MAGNETOSPHERE ORIGINATED IN THE VOLCANIC ATMOSPHERE OF THE SMALL MOON IO. SULFUR AND OXYGEN GAS IS IONIZED PICKED UP BY THE RAPIDLY ROTATING JOVIAN MAGNETIC FIELD AND EFFECTIVELY TRAPPED IN THE TORUS WHERE THE PLASMA FORMS IDENTIFIABLE REGIONS WITH DISTINCT CHEMICAL AND THERMAL CHARACTERISTICS. OVER TIME TORUS MATERIAL SLOWLY DIFFUSES RADIALLY OUTWARD WHERE ITS HEAVY IONS DISTORT THE SHAPE OF THE OUTER MAGNETOSPHERE AND IS EVENTUALLY LOST FROM THE MAGNETOSPHERE. DENSITY VARIATIONS WITH JOVIAN LONGITUDE OF THE PLASMA TORUS ARE IMPORTANT FOR UNDERSTANDING THE SYSTEM'S BEHAVIOR. HOWEVER THEIR NATURE IS NEITHER WELL CHARACTERIZED BY OBSERVATIONS NOR EXPLAINED BY THEORY. HERE WE WILL PROVIDE AND INTERPRET NEW CONSTRAINTS ON THE DENSITY STRUCTURE OF THE TORUS. THE PLASMA DISTRIBUTION WILL BE MEASURED BY THREE COMPLEMENTARY TECHNIQUES: JUNO RADIO OCCULTATIONS DURING PERIJOVE PASSES COORDINATED GROUND-BASED VISIBLE LIGHT OBSERVATIONS AND NEAR-CONTINUOUS HISAKI ULTRAVIOLET OBSERVATIONS. RADIO OCCULTATIONS ON EACH ORBIT ARE SENSITIVE TO THE BULK DENSITY OF THE INNER TORUS. THESE MEASUREMENTS PROVIDE A RARE AND COMPREHENSIVE VIEW OF LATITUDINAL STRUCTURE AND CAN ISOLATE A NARROW LONGITUDE SECTOR OF THE TORUS THOUGH THEY INTEGRATE THROUGH RADIAL STRUCTURE OVER THE SIGHT LINE. MORE FREQUENT GROUND-BASED OBSERVATIONS OFFER US A SYNOPTIC VIEW THAT PROBES LONGITUDE STRUCTURE AS JUPITER ROTATES. HOWEVER LINE OF SIGHT EFFECTS MUST BE DECONVOLVED TO RECOVER RADIAL STRUCTURE AND LATITUDINAL INFORMATION IS NOT GENERALLY OBTAINED. HISAKI PROVIDES FREQUENT OBSERVATIONS OF SCALE HEIGHT AND ION TEMPERATURE. TOGETHER THESE TWO MEASUREMENTS CAN DISENTANGLE THE COMPLEX PROPERTIES OF THE DISTINCT REGIONS OF THE TORUS. WHILE THE WARM OUTER TORUS HAS BEEN WELL EXPLORED BY UV SPECTROSCOPY (E.G. CASSINI AND HISAKI) RELATIVELY LITTLE IS KNOWN ABOUT THE DENSE REGION INTERIOR TO IO'S ORBIT (THE COLD TORUS). JUNO DATA FROM THE FIRST TEN PERIJOVES HAVE BEEN ARCHIVED IN THE NASA PLANETARY DATA SYSTEM. THESE DATA PROVIDE REASONABLE SAMPLING OF JOVIAN SYSTEM III LONGITUDE WHICH HAS PREVIOUSLY BEEN SHOWN TO INFLUENCE MANY PHENOMENA IN JUPITER'S MAGNETOSPHERE. EXTENSIVE COMPLEMENTARY GROUND-BASED OBSERVATIONS ARE AVAILABLE FROM TIMES AROUND THESE PERIJOVES. WE WILL TEST HOW LATITUDINAL STRUCTURE IN THE TORUS DEPENDS ON SYSTEM III LONGITUDE AND PROXIMITY TO IO. DEVIATIONS FROM EXPECTED LOCATION PROVIDE INDEPENDENT CONSTRAINTS ON THE PLASMA TEMPERATURE AND JUPITER'S MAGNETIC FIELD GEOMETRY WHICH JUNO HAS FOUND TO BE SIGNIFICANTLY MORE COMPLEX THAN EXPECTED. WE WILL ALSO TEST HOW TORUS DENSITIES DEPEND ON SYSTEM III LONGITUDE AND IO'S PROXIMITY. THIS PROPOSAL IS RELEVANT TO THE NEW FRONTIERS DATA ANALYSIS PROGRAM AS IT WILL ENHANCE THE RETURN OF THE JUNO MISSION BY PROVIDING AN ENTIRELY NEW SCIENCE INVESTIGATION THAT BROADENS JUNO'S CURRENT SCIENTIFIC SCOPE. ADDITIONALLY THE PROPOSED STUDY OF THE EQUATORIAL MAGNETOSPHERE COMPLEMENTS THE JUNO TEAM'S ONGOING WORK IN THE POLAR REGION SINCE JUPITER'S FIELD LINES CONNECT THESE TWO REGIONS.