Arrangement of the anode, tray, and probes in the 3DPX device.
Dispersion relation for a driven DAW in 3DPX for an experiment performed at: , , , , (floating), and . Four features are identified in this data. Open squares: at frequencies below , the applied modulation causes a “sloshing” motion of the entire cloud and there is no synchronization. Solid squares: in the range to 220 rad/s, the waves become synchronized to the applied modulation. Solid circle: this point identifies the properties of the self-excited DAW frequency. Open circles: for applied frequencies above the self-excited DAW frequency the waves become unsynchronized from the applied modulation.
Shift in the dust particle cloud as a function of the bias voltage applied to the tray. The two horizontal lines in the image indicate the highest position of the top of the cloud (upper, red line) and lowest position of the bottom (lower, blue line) of the particle cloud for these images. The background experimental conditions are: , , and . Going from left to right, the bias voltage on the tray is increasing. The settings on the tray are given in voltage/current pairs, , , , , and . No modulation is applied to the cloud for this case.
(a) Image of a dust cloud and the interrogation region (32 pixel wide, yellow box) used for determining the light intensity profile. The interrogation region is oriented along the direction of propagation of the DAW. The orientation of the interrogation box has at the bottom of the cloud and at the top of the cloud. The motion of the waves is in the -direction. (b) The light scattering intensity profile plotted in the direction from (a). Here the large amplitude fluctuations in the scattered light correspond to peaks and troughs in the waves (thin, red curve) are compared to a sinusoidal fit (thick, blue curve). From the fit, the wavenumber of the waves can be determined.
Comparison the real (solid curve) and imaginary (dashed curve) parts of the wavenumber as a function for the dust number density modeled for and . The dash-dotted curve represents the calculation of the dust grain charge as a function of the dust number density.
Comparison between the experimental measurements and several theoretical curves of the calculation of vs for different dust kinetic temperatures. The results are shown for two different pressures: (a) and (b) . The four dust kinetic temperatures are given by: 50 eV (dots, green), 200 eV (dot-dash, red), 300 eV (solid line, blue), and 400 eV (dash, black). The experimental data for these two cases is shown as open circles in both figures.
Dispersion relation data from Fig. 2 in the regime where the waves are synchronized to the applied modulation (solid squares) and the self-excited (solid square) DAW. Calculations are shown for the same four cases of the dust kinetic temperature: 50 eV (dots, green), 200 eV (dot-dashed, red), 300 eV (solid line, blue), and 400 eV (dash, black).
Plot of the velocity distribution in each vector direction for a particle cloud at . The distribution for each vector direction is shown: (open circles), (closed circles), and (open squares). An estimate of the dust kinetic temperature in each vector direction is also given: , , and .
Operational parameters for 3DPX device.
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