The Fast Plasma Investigation (FPI) was developed for flight on the Magnetospheric Multiscale (MMS) mission to measure the differential directional flux of magnetospheric electrons and ions with ...unprecedented time resolution to resolve kinetic-scale plasma dynamics. This increased resolution has been accomplished by placing four dual 180-degree top hat spectrometers for electrons and four dual 180-degree top hat spectrometers for ions around the periphery of each of four MMS spacecraft. Using electrostatic field-of-view deflection, the eight spectrometers for each species together provide 4pi-sr-field-of-view with, at worst, 11.25-degree sample spacing. Energy/charge sampling is provided by swept electrostatic energy/charge selection over the range from 10 eVq to 30000 eVq. The eight dual spectrometers on each spacecraft are controlled and interrogated by a single block redundant Instrument Data Processing Unit, which in turn interfaces to the observatory's Instrument Suite Central Instrument Data processor. This paper described the design of FPI, its ground and in-flight calibration, its operational concept, and its data products.
The Lunar Environment heliospheric X-ray Imager (LEXI) is a wide field-of-view soft X-ray telescope developed to study solar wind-magnetosphere coupling. LEXI is part of the Blue Ghost 1 mission ...comprised of 10 payloads to be deployed on the lunar surface. LEXI monitors the dayside magnetopause position and shape as a function of time by observing soft X-rays (0.1–2 keV) emitted from solar wind charge-exchange between exospheric neutrals and high charge-state solar wind plasma in the dayside magnetosheath. Measurements of the shape and position of the magnetopause are used to test temporal models of meso- and macro-scale magnetic reconnection. To image the boundary, LEXI employs lobster-eye optics to focus X-rays to a microchannel plate detector with a 9.1
×
∘
9.1
∘
field of view.
The Cusp Plasma Imaging detector (CuPID) Cube Satellite Observatory is a six‐unit Cube Satellite developed to study macroscale properties of dayside magnetopause reconnection. Reconnection will be ...studied through imaging spatial and temporal ion dispersion signatures in the magnetospheric cusps. As reconnection enables shocked solar wind plasma to enter the cusp, high charge state solar wind ions will charge‐exchange with Earth's neutral exosphere. This process generates soft X‐rays imaged by the spacecraft. CuPID is in a circular, highly inclined (97.6°), sun‐synchronous, low Earth orbit (550 km), where it views upward through the cusp from its low altitude footprint. The mission carries three science instruments, an energetic (>50 keV) radiation detector, a soft X‐ray (0.1–2 keV) imager, and a body‐mounted magnetometer. The soft X‐ray imager employs a novel, wide field‐of‐view (4.6°) slumped micropore optical element to focus X‐rays. The radiation detector uses collimated micro‐dosimeters with blocking foils to discriminate particle species. The three‐axis magnetometer is part of the attitude determination and control system and has been calibrated to provide scientifically useful data.
Plain Language Summary
The Cusp Imaging Plasma Instrument Detector (CuPID) CubeSat Observatory is a small spacecraft designed to study soft X‐rays from space. These X‐rays will not penetrate the Earth's atmosphere, so an observer must make measurements from space, and CuPID will fly in a low altitude (550 km) polar orbit. The spacecraft will carry the first ever wide field‐of‐view soft X‐ray imager into orbit to make measurements of the Earth's space environment in soft X‐rays. Scientifically, soft X‐rays are useful as their intensity and dynamics in the Earth's polar cusps provide a proxy for the driving from the sun's solar wind. The spacecraft packs a modular set of avionics as well as soft X‐ray telescope and radiation sensor into a small 10 cm × 20 cm × 30 cm box. The self‐sustained mission will provide the first regular images of the Earth's magnetic field and space environment in soft X‐rays.
Key Points
The Cusp Plasma Imaging detector (CuPID) Cube Satellite Observatory is a small satellite built to study soft X‐rays in space
CuPID is a pioneering wide field‐of‐view soft X‐ray imager in orbit
CuPID studies solar wind‐magnetosphere coupling and magnetopause reconnection
The IBEX-Lo Sensor Fuselier, S. A.; Bochsler, P.; Chornay, D. ...
Space science reviews,
08/2009, Volume:
146, Issue:
1-4
Journal Article
Peer reviewed
Open access
The IBEX-Lo sensor covers the low-energy heliospheric neutral atom spectrum from 0.01 to 2 keV. It shares significant energy overlap and an overall design philosophy with the IBEX-Hi sensor. Both ...sensors are large geometric factor, single pixel cameras that maximize the relatively weak heliospheric neutral signal while effectively eliminating ion, electron, and UV background sources. The IBEX-Lo sensor is divided into four major subsystems. The entrance subsystem includes an annular collimator that collimates neutrals to approximately 7°×7° in three 90° sectors and approximately 3.5°×3.5° in the fourth 90° sector (called the high angular resolution sector). A fraction of the interstellar neutrals and heliospheric neutrals that pass through the collimator are converted to negative ions in the ENA to ion conversion subsystem. The neutrals are converted on a high yield, inert, diamond-like carbon conversion surface. Negative ions from the conversion surface are accelerated into an electrostatic analyzer (ESA), which sets the energy passband for the sensor. Finally, negative ions exit the ESA, are post-accelerated to 16 kV, and then are analyzed in a time-of-flight (TOF) mass spectrometer. This triple-coincidence, TOF subsystem effectively rejects random background while maintaining high detection efficiency for negative ions. Mass analysis distinguishes heliospheric hydrogen from interstellar helium and oxygen. In normal sensor operations, eight energy steps are sampled on a 2-spin per energy step cadence so that the full energy range is covered in 16 spacecraft spins. Each year in the spring and fall, the sensor is operated in a special interstellar oxygen and helium mode during part of the spacecraft spin. In the spring, this mode includes electrostatic shutoff of the low resolution (7°×7°) quadrants of the collimator so that the interstellar neutrals are detected with 3.5°×3.5° angular resolution. These high angular resolution data are combined with star positions determined from a dedicated star sensor to measure the relative flow difference between filtered and unfiltered interstellar oxygen. At the end of 6 months of operation, full sky maps of heliospheric neutral hydrogen from 0.01 to 2 keV in 8 energy steps are accumulated. These data, similar sky maps from IBEX-Hi, and the first observations of interstellar neutral oxygen will answer the four key science questions of the IBEX mission.
Using ion–electron fluid parameters derived from Cassini Plasma Spectrometer (CAPS) observations within Saturn's inner magnetosphere as presented in Sittler et al. 2006a. Cassini observations of ...Saturn's inner plasmasphere: Saturn orbit insertion results. Planet. Space Sci., 54, 1197–1210, one can estimate the ion total flux tube content,
N
ION
L
2, for protons, H
+, and water group ions, W
+, as a function of radial distance or dipole
L shell. In Sittler et al. 2005. Preliminary results on Saturn's inner plasmasphere as observed by Cassini: comparison with Voyager. Geophys. Res. Lett. 32(14), L14S04), it was shown that protons and water group ions dominated the plasmasphere composition. Using the ion–electron fluid parameters as boundary condition for each
L shell traversed by the Cassini spacecraft, we self-consistently solve for the ambipolar electric field and the ion distribution along each of those field lines. Temperature anisotropies from Voyager plasma observations are used with
(
T
⊥
/
T
∥
)
W
+
∼
5
and
(
T
⊥
/
T
∥
)
H
+
∼
2
. The radio and plasma wave science (RPWS) electron density observations from previous publications are used to indirectly confirm usage of the above temperature anisotropies for water group ions and protons. In the case of electrons we assume they are isotropic due to their short scattering time scales. When the above is done, our calculation show
N
ION
L
2 for H
+ and W
+ peaking near Dione's
L shell with values similar to that found from Voyager plasma observations. We are able to show that water molecules are the dominant source of ions within Saturn's inner magnetosphere. We estimate the ion production rate
S
ION∼10
27
ions/s as function of dipole
L using
N
H
+
,
N
W
+
and the time scale for ion loss due to radial transport
τ
D
and ion–electron recombination
τ
REC. The ion production shows localized peaks near the
L shells of Tethys, Dione and Rhea, but not Enceladus. We then estimate the neutral production rate,
S
W, from our ion production rate,
S
ION, and the time scale for loss of neutrals by ionization,
τ
ION, and charge exchange,
τ
CH. The estimated source rate for water molecules shows a pronounced peak near Enceladus’
L shell
L∼4, with a value
S
W∼2×10
28
mol/s.
We report initial results from the VISualizing Ion Outflow via Neutral atom imaging during a Substorm (VISIONS) rocket that flew through and near several regions of enhanced auroral activity and also ...sensed regions of ion outflow both remotely and directly. The observed neutral atom fluxes were largest at the lower energies and generally higher in the auroral zone than in the polar cap. In this paper, we focus on data from the latter half of the VISIONS trajectory when the rocket traversed the polar cap region. During this period, many of the energetic neutral atom spectra show a peak at 100eV. Spectra with peaks around 100eV are also observed in the Electrostatic Ion Analyzer (EIA) data consistent with these ions comprising the source population for the energetic neutral atoms. The EIA observations of this low energy population extend only over a few tens of km. Furthermore, the directionality of the arriving energetic neutral atoms is consistent with either this spatially localized source of energetic ions extending from as low as about 300km up to above 600km or a larger source of energetic ions to the southwest.
Increasing the temporal resolution and instant coverage of velocity space of space plasma measurements is one of the key issues for experimentalists. Today, the top-hat plasma analyzer appears to be ...the favorite solution due to its relative simplicity and the possibility to extend its application by adding a mass-analysis section and an electrostatic angular scanner. Similarly, great success has been achieved in MMS mission using such multiple top-hat analyzers to achieve unprecedented temporal resolution. An instantaneous angular coverage of charged particles measurements is an alternative approach to pursuing the goal of high time resolution. This was done with 4-D Fast Omnidirectional Nonscanning Energy Mass Analyzer and, to a lesser extent, by DYMIO instruments for Mars-96 and with the Fast Imaging Plasma Spectrometer instrument for MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission. In this paper we describe, along with precursors, a plasma analyzer with a 2 electrostatic mirror that was developed originally for the Phobos-Soil mission with a follow-up in the frame of the BepiColombo mission and is under development for future Russian missions. Different versions of instrument are discussed along with their advantages and drawbacks.
We present new and definitive results of Cassini plasma spectrometer (CAPS) data acquired during passage through Saturn's inner plasmasphere by the Cassini spacecraft during the approach phase of the ...Saturn orbit insertion period. This analysis extends the original analysis of Sittler et al. 2005. Preliminary results on Saturn's inner plasmasphere as observed by Cassini: comparison with Voyager. Geophys. Res. Lett. 32, L14S07,
doi:10.1029/2005GL022653 to
L∼10 along with also providing a more comprehensive study of the interrelationship of the various fluid parameters. Coincidence data are sub-divided into protons and water group ions. Our revised analysis uses an improved convergence algorithm which provides a more definitive and independent estimate of the spacecraft potential
Φ
SC for which we enforce the protons and water group ions to co-move with each other. This has allowed us to include spacecraft charging corrections to our fluid parameter estimations and allow accurate estimations of fluctuations in the fluid parameters for future correlative studies. In the appendix we describe the ion moments algorithm, and minor corrections introduced by not weighting the moments with sin
θ term in Sittler et al. 2005 (Correction offset by revisions to instruments geometric factor). Estimates of the spacecraft potential and revised proton densities are presented. Our total ion densities are in close agreement with the electron densities reported by Moncuquet et al. 2005. Quasi-thermal noise spectroscopy in the inner magnetosphere of Saturn with Cassini/RPWS: electron temperatures and density. Geophys. Res. Lett. 32, L20S02,
doi:10.1029/2005GL022508 who used upper hybrid resonance (UHR) emission lines observed by the radio and plasma wave science (RPWS) instrument. We show a positive correlation between proton temperature and water group ion temperature. The proton and thermal electron temperatures track each with both having a positive radial gradient. These results are consistent with pickup ion energization via Saturn's rotational electric field. We see evidence for an anti-correlation between radial flow velocity
V
R and azimuthal velocity
V
φ
, which is consistent with the magnetosphere tending to conserve angular momentum. Evidence for MHD waves is also present. We show clear evidence for outward transport of the plasma via flux tube interchange motions with the radial velocity of the flow showing positive radial gradient with
V
R
∼
0.12
(
L
/
4
)
5.5
km
/
s
functional dependence for 4<
L<10 (i.e., if we assume to be diffusive transport then
D
LL
∼
D
0
L
11
for fixed stochastic time step
δt). Previous models with centrifugal transport have used
D
LL
∼
D
0
L
3
dependence. The radial transport seems to begin at Enceladus’
L shell,
L∼4, where we also see a minimum in the
W
+ ion temperature
T
W
∼
35
eV
. For the first time, we are measuring the actual flux tube interchange motions in the magnetosphere and how it varies with radial distance. These observations can be used as a constraint with regard to future transport models for Saturn's magnetosphere. Finally, we evaluate the thermodynamic properties of the plasma, which are all consistent with the pickup process being the dominant energy source for the plasma.
We present an analysis of Saturn's inner plasmasphere as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere when the spacecraft ...was inserted into orbit around Saturn. The ion fluxes are divided into two sub‐groups: protons and water group ions. We present the relative amounts of these two groups and the first estimates of their fluid parameters: ion density, flow velocity and temperature. We also compare this data with electron plasma measurements. Within the plasmasphere and inside of Enceladus' orbit, water group ions are about a factor of ∼10 greater than protons in number with number densities exceeding 40 cm−3. Within this inner region the spacecraft acquires a negative potential so that the electron density is underestimated. The electron and proton temperatures, which could not be measured in this region by Voyager, are T ∼ 2 eV at L ∼ 3. Also, within this inner region the protons, because of a negative spacecraft potential, appear to be super‐corotating. By enforcing the condition that protons and water group ions are co‐moving we may be able to acquire an independent estimate of the spacecraft potential relative to that estimated when comparing ion‐electron measurements. Using our estimates of plasma properties, we estimate the importance of the rotating plasma on the stress balance equation for the inner magnetosphere and corresponding portion of the ring current.
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