SCIENCE OBJECTIVES. THE MAIN OBJECTIVE OF THIS PROJECT IS TO CONDUCT A STATISTICAL ANALYSIS USING A LARGE SET OF SIMULTANEOUS MEASUREMENTS OF FIELD AND PLASMA DATA TO ESTABLISH A DETAILED COMPARISON OF THE SCALING PROPERTIES OF SOLAR WIND TURBULENCE WITH THE MOST RECENT ADVANCES IN INCOMPRESSIBLE MAGNETOHYDRODYNAMICS (MHD) TURBULENCE THEORY AND SIMULATIONS. WE AIM TO ACCOMPLISH THE FOLLOWING SCIENTIFIC GOALS: 1) INVESTIGATE THE EXISTENCE OF SCALING LAWS FOR THE ALIGNMENT ANGLE BETWEEN VELOCITY AND MAGNETIC FIELD FLUCTUATIONS ALSO KNOWN AS SCALE-DEPENDENT DYNAMIC ALIGNMENT (SDDA) 2) INVESTIGATE THE POSSIBLE THREE DIMENSIONAL NATURE OF THE SDDA 3) INVESTIGATE THE ROLE OF THE CROSS-HELICITY RESIDUAL ENERGY AND THE COMPRESSIBILITY ON THE SCALING OF DYNAMICAL ALIGNMENT. ONE OF THE MOST IMPORTANT RECENT DEVELOPMENTS IN MHD TURBULENCE THEORY IS THAT THE EXISTENCE OF SDDA FOR INSTANCE BETWEEN VELOCITY AND MAGNETIC AND/OR ELSASSER FIELDS CAN LEAD TO A SCALE-DEPENDENT DEPLETION OF THE NONLINEAR INTERACTIONS BETWEEN TURBULENT FLUCTUATIONS WHICH IN TURN AFFECTS THE SHAPE OF THE TURBULENCE SPECTRUM AND THE TURBULENCE ANISOTROPY. THE MOST PROMISING PHENOMENOLOGICAL MODELS OF INCOMPRESSIBLE MHD TURBULENCE HAVE IN COMMON GOLDREICH AND SRIDHAR S ASSUMPTION OF CRITICAL BALANCE I.E. THAT THE TIME SCALE ASSOCIATED WITH LINEAR WAVE PROPAGATION IS COMPARABLE WITH THE NONLINEAR CASCADE TIME. BROADLY SPEAKING THESE MODELS CAN BE GROUPED INTO THOSE THAT INCLUDE SDDA IN THE CRITICAL BALANCE CONDITION AND THOSE THAT DO NOT RESULTING IN DIFFERENT PREDICTIONS FOR THE SCALING PROPERTIES OF TURBULENCE SPECTRA SDDA AND TURBULENCE ANISOTROPY. ALTHOUGH SEVERAL NUMERICAL SIMULATIONS TO DATE HAVE SHOWN STRONG EVIDENCE FOR THE EXISTENCE OF A SDDA LARGELY CONSISTENT WITH THEORETICAL PREDICTIONS FOR THE MEASURED ENERGY SPECTRUM CONCLUSIVE OBSERVATIONAL EVIDENCE OF SDDA IS LACKING. ONLY A FEW STUDIES HAVE ATTEMPTED TO MEASURE THE SDDA WITH RESPECT TO THE LENGTH-SCALE OF SOLAR WIND FLUCTUATIONS. HOWEVER THESE PREVIOUS STUDIES DID NOT TAKE INTO ACCOUNT THE POSSIBLE EFFECT OF THE SAMPLING DIRECTION IN THE DERIVATION OF THE SCALING OF THE SDDA. ALSO THERE WAS NO ATTEMPT TO INVESTIGATE HOW OTHER PROPERTIES OF THE SOLAR WIND PLASMA SUCH AS CROSS-HELICITY RESIDUAL ENERGY AND COMPRESSIBILITY MAY AFFECT THE SCALING OF THE SDDA. METHODOLOGY. TO STATISTICALLY INVESTIGATE THE SCALING PROPERTIES OF SOLAR WIND TURBULENCE WE WILL USE ANALYSIS OF FIELD AND PLASMA DATA FROM WIND AND ACE SPACECRAFT. 1) TO INVESTIGATE THE SCALING OF THE DYNAMICAL ANGLE BETWEEN MAGNETIC AND VELOCITY FLUCTUATIONS WE WILL FIRST IMPLEMENT A WAVELET TRANSFORMATION FOR THE MAGNETIC FIELD DATA IN ORDER TO ESTIMATE THE LOCAL MEAN MAGNETIC FIELD. IN OUR ANALYSIS WE WILL ESTIMATE THE SDDA TAKING INTO ACCOUNT THE SAMPLING ANGLE OF THE SOLAR WIND FLUCTUATIONS WITH RESPECT TO THE LOCAL MEAN MAGNETIC FIELD. THEN WE IMPLEMENT TAYLOR HYPOTHESIS TO CONNECT THE FREQUENCY OF THE MEASURED FLUCTUATIONS TO THEIR LENGTH-SCALE. 2) TO INVESTIGATE THE THREE DIMENSIONAL NATURE OF THE SDDA WE ANALYZE THE FLUCTUATIONS SAMPLED PARALLEL AND PERPENDICULAR TO THE MAGNETIC FIELD. WE WILL ALSO ANALYZE THE SDDA WITH RESPECT TO THE TWO DIMENSIONAL PERPENDICULAR (WITH RESPECT TO THE LOCAL MEAN MAGNETIC FIELD) DIRECTIONS ONE IN THE DIRECTION OF THE ALIGNMENT AND THE OTHER PERPENDICULAR TO THE ALIGNMENT. 3) WE WILL ALSO RE-INVESTIGATE THE SDDA WITH RESPECT TO THE CROSS HELICITY RESIDUAL ENERGY AND THE COMPRESSIBILITY TO INVESTIGATE THEIR EFFECT ON THE SCALING OF THE DYNAMICAL ALIGNMENT. THIS PROJECT DIRECTLY ADDRESSES ONE OF THE GOALS OF WIND AND CLUSTER MISSIONS E.G. "TO INVESTIGATE BASIC PLASMA PROCESSES OCCURRING IN THE NEAR-EARTH SOLAR WIND" AND ONE OF THE FOUR HIGH-LEVEL SCIENCE GOALS OF THE HELIOPHYSICS DECADAL SURVEY E.G. DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE.