A large ion beam device for laboratory solar wind studies

Ulibarri, Zach; Han, Jia; Horányi, M.; Munsat, T.; Wang, X.; Whittall-Scherfee, Guy; Yeo, Li Hsia

doi:10.1063/1.5011785

Cited by 7 publications

(6 citation statements)

References 47 publications

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“…Alongside the DHP, we placed an Ion Energy Analyzer (IEA) to characterize and monitor the ion flows including their flow energy and current as well as their thermal temperature. The DHP and IEA are offset from the center of the beam far enough to not interfere with each other while still centered within the uniform beam width (Ulibarri et al, 2017). The electron density ( n e ) and temperature ( T e ) are 10 4 –10 7 cm −3 and ∼1 eV.…”

Section: Methodsmentioning

confidence: 99%

“…To test the DHP and understand the current collection by probes in plasma flows, we used a laboratory model 4 mm in diameter with a 0.5 mm insulating rod (Figure 2a; Wang et al, 2018) placed in the Colorado Solar Wind Experiment (CSWE) device (Figure 2b; Ulibarri et al, 2017). The DHP is made of two halves (HS1 and HS2) of ball bearings that are electrically isolated from each other with a Kapton tape.…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, thermal ions are found in the CSWE chamber due to a finite neutral pressure (4 × 10 −5 Torr), which causes a certain degree of ion‐neutral charge exchange collisions. The density ratio between the thermal ions and beam ions is approximately 1 (Ulibarri et al, 2017). These thermal ions can affect the formation of the ambipolar potential, which is discussed in the following section.…”

Section: Methodsmentioning

confidence: 99%

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A Double Hemispherical Probe for Characterizing and Minimizing the Self‐Wake Effects on Probe Measurements

2020

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Space-borne Langmuir probes generally have a self-wake behind themselves due to supersonic relative velocities (Mach number M > 1) between the spacecraft and ambient plasma ions. Such a wake may create difficulties for correctly measuring plasma characteristics. Here we present a new technique-the Double Hemispherical Probe (DHP) to characterize and minimize the self-wake effects on probe measurements. The DHP consists of two hemispheres that are simultaneously swept with a bias voltage to obtain two independent current-voltage (I-V) curves, which are used to identify the wake effects of the probe. A laboratory DHP model is inserted in plasma flows (M > 10) created in the Colorado Solar Wind Experiment (CSWE) chamber. In this case, the ion current is the ram current collected by the upstream hemisphere of the DHP, leaving an ion wake behind the downstream hemisphere. A wide range of the Debye ratio R D (ratio of the probe radius to electron Debye length) is tested, and it is found that (1) when R D < 1, the electron currents collected by the two hemispheres are similar, indicating a uniform electron density around the probe, and (2) when R D > 1, the electron current collected by the downstream hemisphere becomes lower than the upstream, indicating a reduced electron density in the probe's wake due to the ambipolar electric field effect. In this case, the electron density measured by traditional single Langmuir probes will be underestimated. With the DHP, we can use the upstream hemisphere measurements to minimize the self-wake effects.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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A Double Hemispherical Probe for Characterizing and Minimizing the Self‐Wake Effects on Probe Measurements

2020

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“…Now we describe the methods for characterizing, removing, and/or minimizing these effects from the I‐V characteristics. These methods are currently developed under laboratory investigations with a thermal plasma chamber (for Cases I and II), the Colorado Solar Wind Experiment device (for Case III; Ulibarri et al, ), and the dust accelerator (for Case IV; Shu et al, ) at the National Aeronautics and Space Administration/Solar System Exploration Research Virtual Institute's Institute for Modeling Plasma, Atmospheres and Cosmic Dust.…”

Section: Methods Development For Interpretation Of the Dhp's I‐v Charamentioning

confidence: 99%

Development of a Double Hemispherical Probe for Improved Space Plasma Measurements

et al. 2018

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Langmuir probes have been widely used for space plasma measurements for decades. However, there are still challenges in the interpretation of their measurements. Due to the interaction of the ambient plasma with a spacecraft and an onboard probe itself, the local plasma conditions around the probe could be very different from the true ambient plasma of interest. These local plasma conditions are often anisotropic and/or inhomogeneous. Most of the Langmuir probes that are made of a single electrode have difficulties to remove these local plasma effects, introducing errors in the derived plasma characteristics. Directional probes are able to characterize anisotropic and inhomogeneous plasmas. The split Langmuir probe and the Segmented Langmuir Probe have been developed to characterize the plasma flow in the Earth's ionosphere. Here we introduce a new type of a directional Langmuir probe, the Double Hemispherical Probe (DHP), to improve the space plasma measurements in a broad range of scenarios: (a) low‐density plasmas, (b) high surface‐emission (photo and/or secondary electron emission) environments, (c) flowing plasmas, and (d) dust‐rich plasma environments. The DHP consists of two identical hemispheres that are electrically insulated and swept with the same voltages simultaneously. The difference currents between the two hemispheres are used to characterize the anisotropic/inhomogeneous plasma conditions created around the probe, which will be then removed or minimized on the interpretation of their current‐voltage curves. This paper describes the basic concept and design of the DHP sensor, as well as its initial results tested in the laboratory plasma environments.

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“…Experiments are conducted using the Colorado Solar Wind Experiment (CSWE) facility (Ulibarri et al., 2017) (Figure 1). CSWE is housed in a stainless steel, cylindrical chamber 76 cm in diameter and 182 cm in length.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

Laboratory Simulation of Solar Wind Interaction With Lunar Magnetic Anomalies

et al. 2022

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Magnetic anomalies on the surface of the Moon interact with the solar wind plasma flow, resulting in both magnetic and electrostatic deflection/reflection of charged particles. Consequently, surface charging in these regions differs from regions without magnetic fields. Using the Colorado Solar Wind Experiment facility, this interaction is investigated with high‐energy flowing plasmas (100–800 eV beam ions) that are incident upon a magnetic dipole embedded beneath an insulating surface. The dipole moment is perpendicular to the surface. The plasma potential distribution is measured above the surface using an emissive probe. In the dipole lobe regions the surface is charged to significantly higher positive potentials by the un‐magnetized ion beam impinging on the surface while the electrons remain excluded by the magnetic field. At low ion beam energies the results agree with these expectations as the surface potential follows the ion beam energy. However, at high beam energies, the surface potentials in the electron‐shielded lobe regions remain significantly lower than the expected magnitude. Surprisingly, electrons are detected in the shielded regions by a Langmuir probe. A test particle simulation indicates that secondary electrons induced by the high energy ion beams impinging on the surface can enter the shielded regions, thus lowering the surface potential.

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A large ion beam device for laboratory solar wind studies

Cited by 7 publications

References 47 publications

A Double Hemispherical Probe for Characterizing and Minimizing the Self‐Wake Effects on Probe Measurements

A Double Hemispherical Probe for Characterizing and Minimizing the Self‐Wake Effects on Probe Measurements

Development of a Double Hemispherical Probe for Improved Space Plasma Measurements

Laboratory Simulation of Solar Wind Interaction With Lunar Magnetic Anomalies

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