1.3 - Dataset Background

Figure 1.3.1 - A schematic diagram of the data acquisition process. The axial magnetic field strength was increased stepwise every one minute.
In our experiment, the clusters were set into rotation using an axial magnetic field. The magnetic field strength started at 15G for the first minute. And then for every minute, the magnetic field was increased stepwise by 15G increments up to 90G (see figure 1.3.1). So the whole experiment lasted for about 6 minutes. The motion of the cluster rotation was recorded with the use of a video camera at frame rate of 2fps. A tracking software was then used to track the particle trajectories for each frame from the video. As a result, the angular position for each of the particles in a dust cluster can be measured as a function of time. In addition, the angular velocity of the particles and the magnetic field strength can also be obtained. These information was then stored as a raw dataset in MS Excel (.xls) format which was used in this project (see figure 1.3.2).
Figure 1.3.2 - This is the raw dataset for planar-3 which consists of the measured value of the angular velocity, angular velocity and magnetic field strength.
Typically in the Excel dataset, every 3 columns are the values of the angular velocity, the angular position and the magnetic field strength of the dust particles. That is, (w1, q1, B1), (w2, q2, B2), (w3, q3, B3), ... And naturally, these values represents the radial, azimuthal and the axial component in a cylindrical coordinate system in our visualization. The number of columns is determined by the number of particles in the cluster (e.g. 6 x 3 =18 columns for planar-6). The number of frames is determined by the number of frame captured (e.g. 6 x 60 x 2fps = 720 rows for 6minutes of captured video). The dataset is in scattered data format.