THE SCIENCE OBJECTIVES ARE TO THEORETICALLY STUDY HOW THE KINETIC COUPLING OF ELECTRONS AND IONS (PROTONS) VIA COLLISIONAL AND INSTABILITY PROCESSES AFFECT THE LARGE-SCALE DYNAMICS IN THE RADIALLY EXPANDING SOLAR WIND AND TO PERFORM DATA ANALYSIS OF IN SITU OBSERVATIONS FROM THE WIND AND HELIOS SPACECRAFT BETWEEN 0.3 AND 1 AU IN ORDER TO VERIFY THE THEORETICAL MODEL. THE SPECIFIC PROBLEM TO BE INVESTIGATED RELATES TO HOW THE DYNAMICALLY COUPLED SOLAR WIND ELECTRONS AND PROTONS CONTRIBUTE TO THE NEAR ISOTROPIZATION OF THEIR TEMPERATURES THE SO-CALLED SOLAR WIND ISOTROPY PROBLEM AN OBSERVED PHENOMENA WHICH HAS NOT YET BEEN SATISFACTORILY EXPLAINED THEORETICALLY. THE PROPOSED RESEARCH IS RELEVANT TO THE SCIENCE GOAL IDENTIFIED IN THE HELIOPHYSICS DECADAL SURVEY NAMELY TO DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE. MODELING THE SOLAR WIND IS A COMPLEX OUTSTANDING PROBLEM OF SCIENTIFIC INTEREST. AN ASPECT THAT HAS NOT BEEN ADDRESSED SUFFICIENTLY IS THE ROLE OF KINETIC PROCESSES. AMONG THE MOST IMPORTANT KINETIC EFFECTS ARE WAVE-PARTICLE INTERACTIONS BY COLLECTIVELY EXCITED INSTABILITIES AND BINARY COLLISIONAL DISSIPATION. APPROACHES THAT CAN BE FOUND IN THE LITERATURE USUALLY DO NOT TREAT THE WAVE-PARTICLE INTERACTION IN A SELF-CONSISTENT WAY. ALSO THE COLLISIONAL DISSIPATION EFFECTS ARE TREATED IN THE LITERATURE BY ADOPTING THE UNMAGNETIZED PLASMA THEORY WHICH IS AN APPROXIMATION. THE PI RECENTLY FORMULATED A MODEL OF THE RADIALLY EXPANDING SOLAR WIND IN WHICH VARIOUS INSTABILITY PROCESSES ARE SELF-CONSISTENTLY TREATED AND COLLISIONAL DISSIPATION EFFECTS ARE CORRECTLY INCORPORATED BY MAKING USE OF MAGNETIZED PLASMA THEORY. WE WILL ADDRESS THE ISOTROPY PROBLEM BY MAKING USE OF AND EXTENDING THE THEORETICAL MODEL DEVELOPED BY THE PI PETER YOON. A PRELIMINARY WORK SHOWS THAT COLLISIONAL PROCESS OR THE COLLISIONAL AGE EFFECT COULD BE THE DOMINANT MECHANISM THAT LEADS TO THE ISOTROPIZATION OF THE TEMPERATURES WHILE THE INSTABILITIES LIMIT THE UPPER/LOWER BOUNDS OF THE TEMPERATURE ANISOTROPIES. THE PRESENT PROPOSAL WILL MAKE USE OF AND FURTHER EXTEND THIS MODEL IN ORDER TO ADDRESS THE ABOVE-STATED SOLAR WIND ISOTROPY PROBLEM. TO TEST THIS THEORY WE WILL MAKE USE OF IMPROVED ION AND ELECTRON MOMENTS (DENSITY VELOCITY TEMPERATURE AND TEMPERATURE ANISOTROPIES) OF THEIR RESPECTIVE VELOCITY DISTRIBUTION FUNCTIONS (AND THEIR SUB-COMPONENTS) OBTAINED FROM THE HELIOS AND WIND SPACECRAFT DATA OBTAINED BY CO-I CHADI SALEM AT UC BERKELEY. WE WILL FURTHER IMPROVE THE THEORETICAL MODEL BY RELAXING THE ASSUMPTION OF BI-MAXWELLIAN VELOCITY DISTRIBUTION FUNCTION. THE FULL KINETIC EQUATIONS FOR PARTICLES AND WAVES AS WELL AS THE DISPERSION RELATION WILL BE SOLVED BY GRID-BASED NUMERICAL SCHEME. THE IMPROVED NUMERICAL SOLUTIONS CAN BE DIRECTLY COMPARED AGAINST THE MEASURED VELOCITY DISTRIBUTION FUNCTIONS IN THE SOLAR WIND BY THE HELIOS SPACECRAFT. THE THEORETICAL MODEL WILL PREDICT A PARTICULAR STATE IN WHICH THE PLASMA EXISTS GIVEN A SET OF PARAMETERS ALLOWING THE OBSERVED QUANTITIES TO TEST THE VERACITY OF THE MODEL. THE KIND OF SOLAR WIND DESCRIPTION DEVELOPED IN THIS WORK WILL BE USEFUL FOR MODELING THE STATE OF LESS-DEVELOPED SOLAR WIND CLOSER TO THE SUN; PREDICTIONS OF THE TYPE CAN THEREFORE BE TESTED AGAINST PLANNED MEASUREMENTS OF THE NEAR-SUN ENVIRONMENT THAT WILL BE OBTAINED BY THE PARKER SOLAR PROBE.