SCIENCE GOALS AND OBJECTIVES: RECONNECTING TAIL CURRENT SHEETS ARE FORMED IN A SMALL-SCALE ACTIVE REGION SURROUNDING THE MAGNETOTAIL X-LINE WHERE FAST PLASMA FLOWS OR FLOW REVERSALS TAKE PLACE AND WHERE CHARGED PARTICLES ARE DECOUPLED FROM THE MAGNETIC FIELD. THE RECONNECTING CURRENT SHEET THICKNESS IS CONSIDERED TO APPROACH OR BECOME LESS THAN A TYPICAL ION INERTIAL LENGTH (DI) BEFORE MAGNETOTAIL EXPLOSIONS SUCH AS MAGNETIC RECONNECTION AND PLASMA INSTABILITIES. A FUNDAMENTAL QUESTION IS WHAT GOVERNS THE FORMATION OF KINETICSCALE THIN CURRENT SHEETS NEAR THE X-LINE LEADING UP TO ITS EXPLOSION.