Modeling Space Charge Distortions in the sPHENIX TPC using Digital Currents

The sPHENIX Time Projection Chamber (TPC) is designed to measure the momenta of charged particles produced in high-energy ion-ion collisions. Contained within a 1.4 T solenoid magnet, this gaseous, cylindrical tracking detector spans 2.11 meters in length, covering the pseudorapidity range of |η| < 1.1 and full azimuth. This talk will focus on the concept of digital current, emphasizing its critical role in calibrating the space charge distortions in the TPC. Beginning with the primary ionization and subsequent electron drift within the TPC gas, I will explore how the readout data is processed into a digital current representing the ion flow through the detector. The discussion will cover the implementation and status of the digital current and corrections. In addition, I will highlight the effects of localized, high-energy depositions such as low momentum, helical tracks and how these features contribute to space charge distortions.