The Freja F3C Cold Plasma Analyzer

Whalen, B. A.; Knudsen, D. J.; Yau, A. W.; Pilon, A. M.; Cameron, T.; Sebesta, Jerry; McEwen, D. J.; Koehler, J. A.; Lloyd, Nicholas; Pocobelli, G.; Laframboise, J. G.; Li, W.; Lundin, R.; Eliasson, L.; Watanabe, Shigeto; Campbell, Gaylon S.

doi:10.1007/bf00756885

Cited by 29 publications

(14 citation statements)

References 18 publications

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“…The SII differs from the more common “top hat” analyzer [ Carlson et al , 1982] in that its focusing system images the energy distribution (rather than stepping through energy with time), and is optimized for lower‐energy particles [ Whalen et al , 1994; Knudsen et al , 2003]. The resulting particle flux distribution is amplified using a microchannel plate and phosphor screen, then reduced in diameter 3:1 and transferred through a 1‐m‐long coherent fiber‐optic imaging bundle.…”

Section: Mission and Instrumentationmentioning

confidence: 99%

Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

et al. 2009

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[1] The JOULE-II sounding rocket salvo was launched from Poker Flat Rocket Range into weak pulsating aurora following a moderate substorm at 0345 LT on 19 January 2007. We present in situ measurements of ion flow velocity and electric and magnetic fields combined with neutral wind observations derived from ground observations of in situ chemical tracers. Measured ion drifts in the 150-198 km and 92-105 km altitude ranges are consistent withẼ ÂB motion to within 16 m s À1 rms and with neutral wind velocity to within 20 m s À1 , respectively. From these measurements we have calculated the ratio k of the ion cyclotron and ion collision frequencies, finding k = 1 at an altitude of 118 ± 0.3 km. Using direct measurements of ion current, we calculate the Joule heating rate and Pedersen and Hall conductivity profiles for this moderately active event and find height-integrated values of 390 W km À2 and 0.59 and 2.22 S, respectively. We also find that these values would have errors of up to tens of percent without coincident neutral wind measurements, and presumably more so during more active conditions. Ion flow vectors were measured at a rate of 125 s

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Section: Mission and Instrumentationmentioning

confidence: 99%

Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

et al. 2009

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“…As shown in Whalen et al (1994), the finite range of the ion entrance position in the aperture plane results in a small inward spread in the radial focusing (∼10 %) and a symmetric spread in the azimuth focusing (∼5°to 15°), as incident ions near the edge of the sensor are deflected to a slightly smaller radius for a given incident ion energy and azimuth. The detector pixel widths were chosen to optimize the ion energy and angular sampling range and resolution given this de-focusing, and to minimize the differences in size between pixels and the resulting potential amplifier crosstalk, while keeping the design and machining tolerance requirements to an achievable level.…”

Section: Instrument Design and Principle Of Operationmentioning

confidence: 96%

“…In contrast with the top-hat design, the hemispherical electrostatic analyzer (HEA) design (Whalen et al 1994) allows the simultaneous sampling of particles over not only the full 360°range of incident azimuth but also an extended range of energy-per-charge. A timeof-flight gate was added to this design in the thermal plasma analyzer (TPA) on Nozomi (Yau et al 1998b), giving the analyzer a capability to image the mass-resolved velocity distribution of each ion species in two dimensions (2D).…”

Section: Introductionmentioning

confidence: 99%

Imaging and Rapid-Scanning Ion Mass Spectrometer (IRM) for the CASSIOPE e-POP Mission

et al. 2015

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The imaging and rapid-scanning ion mass spectrometer (IRM) is part of the Enhanced Polar Outflow Probe (e-POP) instrument suite on the Canadian CASSIOPE small satellite. Designed to measure the composition and detailed velocity distributions of ions in the ∼ 1-100 eV/q range on a non-spinning spacecraft, the IRM sensor consists of a planar entrance aperture, a pair of electrostatic deflectors, a time-of-flight (TOF) gate, a hemispherical electrostatic analyzer, and a micro-channel plate (MCP) detector. The TOF gate measures the transit time of each detected ion inside the sensor. The hemispherical analyzer disperses incident ions by their energy-per-charge and azimuth in the aperture plane onto the detector. The two electrostatic deflectors may be optionally programmed to step through a sequence of deflector voltages, to deflect ions of different incident elevation out of the aperture plane and energy-per-charge into the sensor aperture for sampling. The position and time of arrival of each detected ion at the detector are measured, to produce an image of 2-dimensional (2D), mass-resolved ion velocity distribution up to 100 times per second, or to construct a composite 3D velocity distribution by combining successive images in a deflector voltage sequence. The measured distributions are then used to investigate ion composition, density, drift velocity and temperature in polar ion outflows and related acceleration and transport processes in the topside ionosphere.

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“…At each E / q , the solid trace denotes the ion trajectory along the center axis, and the dashed and dotted traces illustrate the negligibly small inward spread in radial focusing of “off‐axis” ions from the center axis at the entrance aperture. This inward spread is accompanied by a symmetric spread in the azimuth focusing [ Whalen et al ., ].…”

Section: Sensor Designmentioning

confidence: 99%

Imaging thermal plasma mass and velocity analyzer

Yau

Howarth

2016

JGR Space Physics

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We present the design and principle of operation of the imaging ion mass and velocity analyzer on the Enhanced Polar Outflow Probe (e‐POP), which measures low‐energy (1–90 eV/e) ion mass composition (1–40 AMU/e) and velocity distributions using a hemispherical electrostatic analyzer (HEA), a time‐of‐flight (TOF) gate, and a pair of toroidal electrostatic deflectors (TED). The HEA and TOF gate measure the energy‐per‐charge and azimuth of each detected ion and the ion transit time inside the analyzer, respectively, providing the 2‐D velocity distribution of each major ionospheric ion species and resolving the minor ion species under favorable conditions. The TED are in front of the TOF gate and optionally sample ions at different elevation angles up to ±60°, for measurement of 3‐D velocity distribution. We present examples of observation data to illustrate the measurement capability of the analyzer, and show the occurrence of enhanced densities of heavy “minor” O++, N+, and molecular ions and intermittent, high‐velocity (a few km/s) upward and downward flowing H+ ions in localized regions of the quiet time topside high‐latitude ionosphere.

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The Freja F3C Cold Plasma Analyzer

Cited by 29 publications

References 18 publications

Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

Imaging and Rapid-Scanning Ion Mass Spectrometer (IRM) for the CASSIOPE e-POP Mission

Imaging thermal plasma mass and velocity analyzer

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