THE INDUCED MAGNETOSPHERE OF MARS IS PUNCTUATED BY LOCALIZED BUT STRONG CRUSTAL MAGNETIC FIELDS THAT ARE OBSERVED TO PLAY HOST TO A VARIETY OF PHENOMENA TYPICALLY ASSOCIATED WITH GLOBAL MAGNETIC FIELDS. THESE INCLUDE AURORAL PROCESSES AND PARTICLE PRECIPITATION FIELDALIGNEDCURRENT SYSTEMS AND ION OUTFLOW ALL OF WHICH OCCUR IN MAGNETIC CUSPS. DESPITE THESE OBSERVATIONS AND THEIR ANALOGUES AT WELL-STUDIED BODIES SUCH AS EARTH MARTIAN CUSP PROCESSES ARE NOT WELL UNDERSTOOD. FOR EXAMPLE IT IS NOT KNOWN HOW AND WHERE FIELDALIGNED CURRENT SYSTEMS FORM AND ARE MAINTAINED IN SUCH SMALL MAGNETIC STRUCTURES AND IT IS NOT KNOWN WHETHER CHARGED PARTICLE TRANSPORT (PRECIPITATION AND ESCAPE) IN CUSPS OCCURS CONTINUOUSLY OR ONLY INTERMITTENTLY. THESE REGIONS ARE NOT YET CAPABLE OF BEING SPATIALLY RESOLVED IN GLOBAL SCALE MODELS THAT INCLUDE THE ION KINETICS NECESSARY FOR SIMULATING CHARGED PARTICLE TRANSPORT LONG CUSPS. LOCAL MODELS ARE THEREFORE NECESSARY.SCIENCE GOALS AND OBJECTIVES:OUR PROPOSED INVESTIGATION WILL ADDRESS THREE SCIENTIFIC QUESTIONS RELATED TO PROCESSES THAT TRANSPORT PARTICLES IN MARTIAN NIGHT SIDE MAGNETIC CUSP REGIONS:1. WHAT IS THE DISTRIBUTION OF PLASMA AND ELECTRIC FIELDS ALONG CUSPS?2. HOW AND WHEN DO EXTERNAL CHARGED PARTICLES REACH THE EXOBASE REGION?3. HOW DO CUSP-RELATED PROCESSES INFLUENCE ATMOSPHERIC ION ESCAPE?METHODOLOGY:OUR WORK WILL PROCEED THROUGH TWO RELATED EFFORTS TO MODEL PLASMA MOTION AND ELECTRIC FIELDS IN LOCALIZED CUSP REGIONS ON THE MARTIAN NIGHT SIDE. (1) WE WILL ADAPT AND APPLY AN EXISTING 3D HYBRID MODEL FOR THE MARTIAN GLOBAL PLASMA INTERACTION TO CUSPS. (2) WE WILL ADAPT AND APPLY AN EXISTING 1D PARTICLE-IN-CELL (PIC) MODEL FOR LUNAR MAGNETIC CUSPS REGIONS TO THE MARTIAN CASE. THE MODELS WILL BE RUN FOR A VARIETY OF INPUT CONDITIONS COMPARING THE RESULTS IN ORDER TO DETERMINE THE IMPORTANCE OF ELECTRON KINETICS IN DIFFERENT SITUATIONS. THE MODEL BOUNDARY CONDITIONS WILL BE VARIED FROM HIGHLY IDEALIZED CASES TO MORE REALISTIC SITUATIONS IN ORDER TO BUILD INTUITION ABOUT PROCESSES THAT CONTROL THE DEVELOPMENT AND MAINTENANCE OF POTENTIAL STRUCTURES ALONG CUSPS.RELEVANCE:NASAS SOLAR SYSTEM WORKINGS PROGRAM ...SEEKS TO ADDRESS THE PHYSICAL... PROCESSES THAT AFFECT THE...ATMOSPHERES EXOSPHERES AND MAGNETOSPHERES OF PLANETARY BODIES. OUR PROPOSED EFFORT PROBES PHYSICAL PROCESSES THAT OCCUR IN CUSPS OF MARTIAN MAGNETIC FIELDS. THESE MAGNETOSPHERIC PROCESSES RESULT IN THE LOSS OF ATMOSPHERIC PARTICLES FROM MARS AND THE ENERGETICS OF THE EXOBASE REGION. FURTHER CUSP-RELATED PROCESSES OCCUR ON MANY BODIES THROUGHOUT THE SOLAR SYSTEM. WE USE MODELING TECHNIQUES TO ADDRESS OUR SCIENCE OBJECTIVES AND WILL COMPARE OUR RESULTS TO PUBLISHED DATA ONLY IN A GENERAL SENSE (I.E. WE DO NOT INTEND TO PERFORM DETAILED ANALYSIS OF NASA SPACECRAFT MISSION DATA). THEREFORE WE ASSERT THAT THE PROPOSED EFFORT IS RELEVANT FOR THIS CALL.