TURBULENCE PLAYS A CENTRAL ROLE IN THE DYNAMICS OF TERRESTRIAL AS WELL AS ASTROPHYSICAL PLASMAS INCLUDING THE SOLAR WIND. UNDERSTANDING THE DYNAMICS OF SOLAR WIND IN THE HELIOSPHERE IS IMPORTANT FROM MULTIPLE PERSPECTIVES: SPACE WEATHER PREDICTIONS UNDERSTANDING THE DYNAMICS OF ENERGETIC PARTICLES OF SOLAR/ JOVIAN ORIGIN UNDERSTANDING THE PROPAGATION AND DIFFUSION OF GALACTIC COSMIC RAYS TO NAME A FEW. IN ORDER TO BETTER UNDERSTAND ALL THESE PROCESSES ONE HAS TO UNDERSTAND THE NATURE OF SOLAR WIND TURBULENCE AT A WIDE RANGE OF SCALES AND AT WIDE RANGE OF DISTANCES FROM THE SUN. AS AN EXAMPLE RECENT YEARS HAVE SEEN A SURGE IN STUDIES THAT SHOW A CORRELATION BETWEEN ENHANCED SEP FLUXES AND STRONGLY INTERMITTENT TURBULENT STRUCTURES [1 2 3 4]. THIS HAS GARNERED IN INTEREST IN UNDERSTANDING THE ROLE OF TURBULENCE IN SEP PROPAGATION. SIMILAR ARGUMENTS APPLY TO PROPAGATION AND DIFFUSION OF GALACTIC COSMIC RAYS IN THE HELIOSPHERE. SOME OF OUR PRELIMINARY STUDIES SHOW THAT TURBULENT INTERMITTENT STRUCTURES MIGHT SIGNIFICANTLY MODIFY THE DIFFUSION MEAN FREE PATHS OF HIGH ENERGY PARTICLES IN TURBULENCE. THE ABOVE MENTIONED CONSIDERATIONS CALL FOR A BETTER UNDERSTANDING OF INTERMITTENCY IN THE HELIOSPHERE. TO THE BEST OF OUR KNOWLEDGE A COMPREHENSIVE STUDY OF INTERMITTENCY IN THE HELIOSPHERE STARTING FROM 1AU ALL THE WAY OUT TO A FEW TENS OF AUS DOES NOT EXIST. OUR GOAL IS TO CREATE SUCH A COMPREHENSIVE KNOWLEDGE BASE OF INTERMITTENCY PROPERTIES WHICH CAN IN TURN BE USED TO IMPROVE THE MODELS OF SEP AND GCR PROPAGATION AND DIFFUSION. THE PARTICULAR SCIENCE QUESTIONS THAT WE WILL FOCUS ON TO CREATE SUCH A KNOWLEDGE BASE ARE: 1) DOES THE INTENSITY OF COHERENT STRUCTURES VARY WITH HELIOCENTRIC DISTANCE? 2) WHAT ARE THE WAITING TIME DISTRIBUTIONS OF SUCH INTERMITTENT STRUCTURES? 3) BASED ON THE ANSWERS TO PREVIOUS TWO QUESTIONS IS THERE A WAY TO MODEL THE EVOLUTION OF INTERMITTENCY IN THE HELIOSPHERE? DATA FROM VOYAGER ACE AND WIND SPACECRAFT WILL BE USED IN THIS STUDY. OUR PRELIMINARY WORK SHOWS THAT THE MAGNETIC FIELD DATA FROM VOYAGER SPACECRAFT HAS A SIGNIFICANT FRACTION OF BAD DATA. THIS BAD DATA CAN SEVERELY AFFECT HIGHER ORDER STATISTICS. HENCE CLEANING OF THE DATA IS CRUCIAL TO THIS STUDY. BASED ON OUR CORRESPONDENCE WITH VOYAGER CO-I BURLAGA AND OUR OWN TESTS THE CLEANING WILL BE DONE IN A FEW MONTHS. AFTER CLEANING THE DATA SETS THE STANDARD INTERMITTENCY TESTS WILL BE DONE ON THESE DATA SETS TO ADDRESS THE ABOVE MENTIONED SCIENCE QUESTIONS.
$523,109FY2020National Aeronautics and Space AdministrationNASA
University Of Delaware, Newark DE