Impact of particle charge and electrorheology-effects on dust-acoustic waves in low pressure complex plasma under microgravity

Abstract This study investigates the influence of particle charge and electrorheological (ER) effects on microparticle dynamics and dust-acoustic wave propagation in low-pressure complex plasmas under microgravity conditions. Experiments were conducted using PK-4 during parabolic flights and onboard the International Space Station to analyze dust particle behavior in direct current (DC) and DC polarity switching discharge plasma. Key findings reveal that variations in particle charge potential and ER effects significantly affect particle dynamics, especially at different gas pressures. Specifically, we validated a dimensionless charge potential of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.34</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> </mml:math> in a DC neon plasma discharge, noting a rapid increase in this potential at pressures below 15 Pa. Furthermore, we observed a reduction in charge of up to 50% due to quadrupole effects induced by polarity switching. These results provide critical insights into plasma behavior in microgravity and the role of external electric fields in particle interactions.