MARS LACKS A GLOBAL INTRINSIC MAGNETIC FIELD BUT POSSESSES REGIONS OF STRONG CRUSTAL MAGNETIC FIELD THAT ARE CONCENTRATED IN THE SOUTHERN HEMISPHERE. STUDIES OF MARS GLOBAL SURVEYOR AND MARS EXPRESS DATA HAVE SHOWN THAT THE IONOSPHERIC ELECTRON DENSITY CAN BE ENHANCED IN THESE STRONG CRUSTAL FIELD REGIONS ESPECIALLY WHERE THE FIELD TOPOLOGY IS VERTICAL. RECENT DATA FROM NASA'S MARS ATMOSPHERE AND VOLATILE EVOLUTION (MAVEN) MISSION PROVIDE AN OPPORTUNITY TO EXPAND UPON THESE EARLIER STUDIES BECAUSE THE MAVEN DATA ARE THE FIRST TO INCLUDE COMPREHENSIVE PLASMA AND MAGNETIC FIELD MEASUREMENTS AND MEASUREMENTS OF THE IONOSPHERIC COMPOSITION. THE GOAL OF THE PROPOSED WORK IS TO UNDERSTAND HOW CRUSTAL FIELDS INFLUENCE THE DENSITY COMPOSITION AND ELECTRODYNAMICS OF THE MARTIAN IONOSPHERE. THIS WILL BE ACHIEVED PRIMARILY THROUGH ANALYSIS OF MAVEN DATA ALONG WITH MODELING WORK TO FACILITATE THE INTERPRETATION OF THE MAVEN DATA. THE DATA ANALYSIS EFFORT WILL INCLUDE BOTH DETAILED CASE STUDIES AND GLOBAL LONG-TERM SURVEYS.