RESUMO
Experimental evidence of the existence of an intermediate region between a capacitively coupled plasma and the collisional space-charge region at its borders is presented. This proof is generated by monitoring-in an airplane carrying out parabolic flights-the trajectory of plasma-confined microparticles. Based on only primary data and without the need for a sophisticated model, our analysis concludes a sharply marked transition from the sheath region into another region with a significantly lower-yet nonzero-space-charge density, i.e., a region which is often called the presheath.
RESUMO
We present an absolute measurement of the total ion-drag force on one single microparticle at the edge of the dust free region in low pressure complex plasmas: the void. In order to do so, the particle confinement position was monitored as a function of the gas pressure for two particle sizes under normal gravity conditions and under microgravity conditions during parabolic flights. At the border of the void, the ion-drag force on a particle with a radius of 4.90 µm appeared to be (3.6±0.3)×10(-12) N.
