Characteristics of the plasma from A 94 kms−1 micro-particle impact

Ratcliff, P.R.; Allahdadi, Firooz A.

doi:10.1016/0273-1177(95)00763-5

Cited by 26 publications

(19 citation statements)

References 9 publications

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“…The range of ion energies required to fit peaks in the flight spectra is greater than previously reported in some laboratory experiments. For higher-velocity impacts, our results are in good agreement with both Ratcliff and Allahdadi (1996) and Hornung et al (1996), with ion energies of hundreds of eV. For the low-velocity impacts (o10 km s À1 ), which produce cluster ion spectra, we obtain good fits to the data using ion energies of up to $80 eV, contrasting with the results of Friichtenicht, quoted by Ratcliff and Allahdadi (1996), of 0.5 eV for metallic target ions (impact velocities of 17-47 km s À1 ).…”

Section: Discussionsupporting

confidence: 81%

“…For higher-velocity impacts, our results are in good agreement with both Ratcliff and Allahdadi (1996) and Hornung et al (1996), with ion energies of hundreds of eV. For the low-velocity impacts (o10 km s À1 ), which produce cluster ion spectra, we obtain good fits to the data using ion energies of up to $80 eV, contrasting with the results of Friichtenicht, quoted by Ratcliff and Allahdadi (1996), of 0.5 eV for metallic target ions (impact velocities of 17-47 km s À1 ). The ion energies we derived for low-velocity impacts do, however, agree with those found by Burchell et al (1996) of tens of eV and we remain unable to explain the discrepancy with Friichtenicht's results.…”

Section: Discussionsupporting

confidence: 81%

“…In fact, if we apply narrow ion angular emission distribution functions such as cos 3 (y) (Ratcliff and Allahdadi, 1996), we produce peaks which are broader than those observed in CDA flight spectra. Furthermore, the pronounced 'tail' of the peaks is not produced.…”

Section: Discussionmentioning

confidence: 99%

“…ion focussing along the target surface normal) used by others. Indeed, the distributions derived in Ratcliff and Allahdadi (1996) varied according to the energy of the ion species, implying that the instrument configuration (and hence response function) used in their experiment was dominating the shape of their spectral peaks. (3) We find that a wide range of ion energies (up to hundreds of eV) are required to fit peaks seen in flight spectra, and that this is independent of any assumption about the ions' angular distribution.…”

Section: Discussionmentioning

confidence: 99%

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Modelling CDA mass spectra

Hillier¹,

McBride²,

Green³

et al. 2006

Planetary and Space Science

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We present the initial results from a simulation of ion behaviour within Cassini's cosmic dust analyser (CDA) instrument, using an inhouse ion dynamics code. This work is to enable and enhance the detailed interpretation of dust impact ionisation mass spectra returned from the Saturnian system. Early work has already provided insights into the properties of the impact plasma in both low-and highvelocity impacts. We find that the isotropic emission of ions from the impact plasma successfully reproduces features seen in flight spectra and that the emitted ions have a higher range of energies (tens to hundreds of eV) than previously reported in some studies. Using these new ion characteristics, we have successfully modelled CDA flight mass spectra. r

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Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Modelling CDA mass spectra

Hillier¹,

McBride²,

Green³

et al. 2006

Planetary and Space Science

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“…1,2 In addition, chemical reactions, including dissociation and recombination, can take place within the resultant fluid phases, especially in gas-phase and ionized species. [3][4][5] Understanding the chemical changes associated with impacts is essential to understanding the impact accretion planetary formation process as it occurs on different lengths and timescales upon the initial differentiation and evolution of planets. Toward the end of the Earth's accretion, impacts from the increasingly larger planetesimals (which themselves accreted to masses within the planetary range) resulted in at least one giant collision that is hypothesized to have resulted in Moon formation.…”

Section: Introductionmentioning

confidence: 99%

Time-of-flight mass spectrometry of mineral volatilization: Toward direct composition analysis of shocked mineral vapor

Austin

Shen

Beauchamp

et al. 2012

Review of Scientific Instruments

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An integrated ion trap and time-of-flight mass spectrometer for chemical and photo-reaction dynamics studies Rev. Sci. Instrum. 83, 043103 (2012) Laser induced and controlled chemical reaction of carbon monoxide and hydrogen J. Chem. Phys. 135, 204303 (2011) Excitonic parameters of GaN studied by time-of-flight spectroscopy Appl. Phys. Lett. 99, 101108 (2011) An LIF characterization of supersonic BO (X2Σ+) and CN (X2Σ+) radical sources for crossed beam studies Rev. Sci. Instrum. 82, 083107 (2011) Additional information on Rev. Sci. Instrum. We have developed an orthogonal-acceleration time-of-flight mass spectrometer to study the volatiles produced when a mineral's shock-compressed state is isentropically released, as occurs when a shock wave, driven into the mineral by an impact, reflects upon reaching a free surface. The instrument is designed to use a gun or explosive-launched projectile as the source of the shock wave, impact onto a flange separating a poor vacuum and the high vacuum (10 −7 Torr) interior of the mass spectrometer, and transmission of the shock wave through the flange to a mineral sample mounted on the highvacuum side of the flange. The device extracts and analyzes the neutrals and ions produced from the shocked mineral prior to the possible occurrence of collateral instrument damage from the shockinducing impact. The instrument has been tested using laser ablation of various mineral surfaces, and the resulting spectra are presented. Mass spectra are compared with theoretical distributions of molecular species, and with expected distributions from laser desorption.

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Dust impact signals on the wind spacecraft

2016

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We analyze waveforms recorded by the Time Domain Sampler of the WAVES experiment on Wind which are similar to impulsive waveforms observed by the S/WAVES experiment on STEREO. These have been interpreted as dust impacts by Meyer‐Vernet et al. and M. L. Kaiser and K. Goetz and extensively analyzed by Zaslavsky et al. The mechanism for coupling the emission to the antennas to produce an electrical signal is still not well understood, however. One suggested mechanism for coupling of the impact to the antenna is that the spacecraft body changes potential with respect to the surrounding plasma but the antennas do not (the body mechanism). Another class of mechanisms, with several forms, is that the charge of the emitted cloud interacts with the antennas. The Wind data show that both are operating. The time domain shapes of the dust pulses are highly variable but we have little understanding of what provides these shapes. One feature of the STEREO data has been interpreted as impacts from high velocity nanoparticles entrained by the solar wind. We have not found evidence for fast nanodust in the Wind data. An appreciable fraction of the impacts observed on Wind is consistent with interstellar dust. The impact rates do not follow a Poisson distribution, expected for random independent events, and this is interpreted as bunching. We have not succeeded in relating this bunching to known meteor showers, and they do not repeat from 1 year to the next. The data suggest bunching by fields in the heliosphere.

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Characteristics of the plasma from A 94 kms−1 micro-particle impact

Cited by 26 publications

References 9 publications

Modelling CDA mass spectra

Modelling CDA mass spectra

Time-of-flight mass spectrometry of mineral volatilization: Toward direct composition analysis of shocked mineral vapor

Dust impact signals on the wind spacecraft

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