Abstract:The interaction between a magnetic field and plasma close to a nonconductive surface is of interest for both science and technology. In space, crustal magnetic fields on celestial bodies without atmosphere can interact with the solar wind. In advanced technologies such as those used in fusion or spaceflight, magnetic fields can be used to either control a plasma or protect surfaces exposed to the high heat loads produced by plasma. In this paper, a method will be discussed for investigating magnetic field plas… Show more
“…Magnetic flux densities calculated at selected points using FEMM 19) are given in Table 3. The mean free paths for the experiment conducted at CASPER are 0.5 mm for ions and 7 mm for electrons 18) . Operating at five times the pressure, the mean free paths for the IRS experiments are approximately one-fifth of these values.…”
Section: Magnetic Fieldmentioning
confidence: 97%
“…The plasma parameters of this experiment are described in Table 2. Additional details concerning the experimental setup and data analysis method can be found in Dropmann et al 18) .…”
Section: Micro-particle Tracking Setupmentioning
confidence: 99%
“…Multiple particle drops were used to create an acceleration map in the field of view of the camera. A more detailed description of this method can be found in Dropmann et al 18) . The measured acceleration is due to multiple forces, the major contributors of which are the electric field force and the neutral drag force.…”
In space technology many concepts for magnetic fields are under discussion for the use in advanced propulsion, shielding from radiation or as aid for thermal protection system for the atmospheric entry of spacecraft. Two experiments have been conducted to investigate the feasibility of using magnetic fields to reduce the heat flux onto a thermal protection system during atmospheric entry. For this purpose a modified heat flux probe with embedded permanent magnets has been exposed to a plasma jet and the structure of the bow shock in front of the probe has been observed using an emission spectroscopy setup. The intensity ratio of ionized argon lines for the experiment with and without magnets has been determined and used to analyze the magnetic field`s impact on the flow. Complementary experiments in a low power capacitively driven plasma have been conducted using micron sized particles as probes to map electric fields in a magnetically perturbed plasma. The results from both experiments are presented and analogies are drawn from both approaches. The experiments have shown that the interactions of the magnetic field with the plasma can create strong electric fields which strongly influence the ions even though the field is too weak to magnetize the ions.
“…Magnetic flux densities calculated at selected points using FEMM 19) are given in Table 3. The mean free paths for the experiment conducted at CASPER are 0.5 mm for ions and 7 mm for electrons 18) . Operating at five times the pressure, the mean free paths for the IRS experiments are approximately one-fifth of these values.…”
Section: Magnetic Fieldmentioning
confidence: 97%
“…The plasma parameters of this experiment are described in Table 2. Additional details concerning the experimental setup and data analysis method can be found in Dropmann et al 18) .…”
Section: Micro-particle Tracking Setupmentioning
confidence: 99%
“…Multiple particle drops were used to create an acceleration map in the field of view of the camera. A more detailed description of this method can be found in Dropmann et al 18) . The measured acceleration is due to multiple forces, the major contributors of which are the electric field force and the neutral drag force.…”
In space technology many concepts for magnetic fields are under discussion for the use in advanced propulsion, shielding from radiation or as aid for thermal protection system for the atmospheric entry of spacecraft. Two experiments have been conducted to investigate the feasibility of using magnetic fields to reduce the heat flux onto a thermal protection system during atmospheric entry. For this purpose a modified heat flux probe with embedded permanent magnets has been exposed to a plasma jet and the structure of the bow shock in front of the probe has been observed using an emission spectroscopy setup. The intensity ratio of ionized argon lines for the experiment with and without magnets has been determined and used to analyze the magnetic field`s impact on the flow. Complementary experiments in a low power capacitively driven plasma have been conducted using micron sized particles as probes to map electric fields in a magnetically perturbed plasma. The results from both experiments are presented and analogies are drawn from both approaches. The experiments have shown that the interactions of the magnetic field with the plasma can create strong electric fields which strongly influence the ions even though the field is too weak to magnetize the ions.
“… Figure 5. Horizontal ( a ) and vertical ( b ) accelerations of the dust particles for a vertically oriented magnet (Dropmann et al. 2015). White lines represent the magnetic field lines.…”
Section: Examples Of Measurementsmentioning
confidence: 99%
“…In another example, magnetic field plasma interactions have been studied using dust particles as probes (Dropmann et al. 2015) by introducing free-falling particles without active control into a plasma. The resulting data have allowed analogies to spectroscopic measurements of ionized argon interacting with a magnetic probe (Knapp et al.…”
In this paper a method is described that allows mapping of the forces acting on dust particles in a GEC reference cell. Monodisperse particles are dropped into the plasma environment and their trajectories are tracked using a high-speed camera system to determine local accelerations and respective forces. Collecting data from a large number of particle drops allows the identification of three-dimensional vector fields for the acting forces. The procedure is described and multiple examples in which the method has been applied are given. These examples include a simple plasma sheath, plasmas perturbed by a horizontal and vertical dipole magnet, an array of multiple magnets mimicking the fields found at a lunar swirl, and the fields inside a glass box used for particle confinement. Further applicability in other plasma environments will be discussed shortly.
In this review, we summarize recent advances in the field of dusty plasmas at strong magnetic fields. Special emphasis is put on situations where experimental laboratory observations are available. These generally comprise dusty plasmas with magnetized electrons and ions, but unmagnetized dust. The fundamental parameters characterizing a magnetized (dusty) plasma are given and various effects in dusty plasmas under magnetic fields are presented. As examples, the reaction of the dust component to magnetic-field modified plasma properties, such as filamentation, imposed structures, dust rotation, nanodusty plasmas and the resulting forces on the dust are discussed. Further, the behavior of the dust charge is described and shown to be relatively unaffected by magnetic fields. Wake field formation in magnetized discharges is illustrated: the strength of the wake field is found to be reduced with increased magnetic field. The propagation of dust acoustic waves in magnetized dusty plasmas is experimentally measured and analyzed indicating that the wave dynamics are not heavily influenced by the magnetic field. Only at the highest fields ($$B> 1$$
B
>
1
T) the wave activity is found to be reduced. Moreover, it is discussed how dust-cyclotron waves might be used to indicate a magnetized dust component. Finally, implications of a magnetized dusty plasma are illustrated.
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