This　work　investigates　the　arc　behaviors　during　the　anode　spot　mode　with　CuCr25　electrodes　using　a　3D　magneto-hydro-dynamic　(MHD)　model.　The　components　considered　in　the　model　include　electrons,　Cu　atoms,　Cr　atoms,　Cu　ions　and　Cr　ions.　The　realistic　axial　magnetic　field　(AMF)　is　generated　by　cup-shaped　electrodes.　When　the　anode　surface　temperature　is　high　enough,　the　anode　vapor　can　enter　the　arc　column　forming　a　cool　and　poorly　conducting　region,　namely　the　neutral　atom　vapor　area　(NAVA).　Simulation　results　show　that　due　to　the　six-leave　shape　of　the　AMF　distribution,　the　current　density　and　the　plasma　temperature　are　the　highest　near　the　slots.　Inside　the　NAVA,　the　plasma　temperature　is　very　low　as　a　result　of　ionization　process　and　the　energy　exchange　among　ions,　atoms　and　electrons.　Similarly,　the　current　density　is　also　considerably　low　because　of　low　electric　conductivity　inside　the　NAVA.　The　highest　atom　density　and　single-charged　ion　density　can　be　seen　in　the　NAVA,　while　the　double-charged　ion　density　reaches　its　maximum　in　front　of　the　NAVA.　This　is　because　ions　are　ionized　to　higher　ionization　levels　step　by　step.　By　comparison,　triple-charged　ion　density　is　negligibly　low　and　reaches　its　maximum　near　the　slots　due　to　high　electron　temperature　here.　©　2020　IEEE.