The escape of CO2+ and other heavy minor ions from Mars

2020 ◽  
Author(s):  
Lukas Maes ◽  
Markus Fraenz ◽  
James McFadden ◽  
Mehdi Benna
Keyword(s):  
Mass Spectra ◽  
Heavy Ion ◽  
Escape Rate ◽  
Neutral Gas ◽  
Peak Fitting ◽  
Ion Escape ◽  
Fitting Method ◽  
Static Data ◽  
Martian Ionosphere ◽  
Ion Species

<p>Next to its main constituent O<sub>2</sub><sup>+</sup>, the Martian ionosphere consists of several other ion species, like CO<sub>2</sub><sup>+</sup>, O<sup>+</sup>, CO<sup>+</sup>, HCO<sup>+</sup>, N2<sup>+</sup>, etc. The ionospheric escape is dominated by O<sub>2</sub><sup>+</sup> and O<sup>+</sup> ions, and as a result the escape of these species is well studied. The other, minor ion species are more difficult to measure in the escaping plasma, because their contribution is typically obscured in the mass spectra of ion instruments by the more abundant O<sub>2</sub><sup>+</sup> peak.</p> <p>In this study we use data from the SupraThermal And Thermal Ion Composition instrument (STATIC) on board MAVEN to investigate the escape of these ions. We use a peak-fitting method to separate the contribution of several ion species, including O<sub>2</sub><sup>+</sup>, CO<sub>2</sub><sup>+</sup>, O<sup>+</sup> and ions with a mass between 28-30 AMU. Our method is validated against Neutral Gas and Ion Mass Spectrometer (NGIMS), also onboard MAVEN, and results in the ionosphere agree qualitatively very well.</p> <p>We apply this method to STATIC data from January 2016 until May 2019 to perform a statistical study examining the escape of low energy (<100 eV) heavy (>=16 AMU) ions throughout the Martian magnetosphere and its surrounding. We find that CO<sub>2</sub><sup>+</sup> ions do escape through the tail but at a very limited rate, namely at less than 1% of the O<sub>2</sub><sup>+</sup> escape rate. Ions with a mass between 28-30 AMU, however, are found to constitute a significant part of the ionospheric outflow, with an escape rate 30% of the O<sub>2</sub><sup>+</sup> rate and 15% of the total heavy ion escape.</p>

scholarly journals Heavy ion escape from Martian wake enhanced by magnetic reconnection

2021 ◽  
Author(s):  
Lei Wang ◽  
Can Huang ◽  
Yasong Ge ◽  
A. M. Du ◽  
Rongsheng Wang ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Flux Rope ◽  
Heavy Ion ◽  
Escape Rate ◽  
Wake Region ◽  
Atmospheric Evolution ◽  
Oxygen Ions ◽  
Plasma Environment ◽  
Ion Escape ◽  
Reconnection Region

Abstract How ion escape from the near-Mars space is one of the biggest puzzles for understanding the atmospheric evolution of Mars. Ions in the plasma wake region continuously escape from the unmagnetized planet. Although the average ion escape rate in the wake region is relatively low, observations also have revealed the presence of events that contribute bursty and enhanced ion escape fluxes. Boundary instabilities and magnetic reconnection are suggested to be the candidate mechanisms. However, there is a lack of evaluation of ion escape caused by reconnection and comparison of the two mechanisms under a similar plasma environment. Here, we show an exciting reconnection event in the Martian wake. Two types of flux ropes are observed during the event. One was generated by reconnection, while others were produced by dayside boundary instability and convected to tail. The escape rate of oxygen ions in the reconnection region was estimated to be about 53–72% of the total tailward escape. Furthermore, the escape flux in the flux rope produced by reconnection was over twice that caused by dayside instabilities.

scholarly journals Apparent and Actual Shifts in Mass and Width of ϕ Mesons Produced in Heavy-Ion Collisions

1997 ◽  
Vol 12 (02) ◽  
pp. 127-134 ◽  
Author(s):  
R. S. Bhalerao ◽  
S. K. Gupta
Keyword(s):  
Invariant Mass ◽  
Preliminary Data ◽  
Heavy Ion Collisions ◽  
Mass Spectra ◽  
Dense Matter ◽  
Heavy Ion ◽  
High Energy ◽  
Mass Shift ◽  
Ion Collisions ◽  
Invariant Mass Spectra

We present a method of analyzing invariant-mass spectra of kaon pairs resulting from decay of ϕ mesons produced in high-energy heavy-ion collisions. It can be used to extract the shifts in the mass and the width (ΔM and ΔΓ) of the ϕ mesons when they are inside the dense matter formed in these collisions. We illustrate our method with the help of available preliminary data. Extracted values of ΔM and ΔΓ are significantly larger than those obtained with an earlier method. Our results are consistent with the experimentally observed pT dependence of the mass shift. Finally, we present a phenomenological relation between ΔM and ΔΓ. It provides a useful constraint on theories which predict the values of these two quantities.

scholarly journals Dissipation of turbulence by magnetohydrodynamic shock waves

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Andrew Lehmann ◽  
Mark Wardle
Keyword(s):  
Shock Front ◽  
Fluid Model ◽  
Neutral Species ◽  
One Dimensional ◽  
Neutral Gas ◽  
Gas Dynamic ◽  
Magnetohydrodynamic Shock ◽  
Two Fluid Model ◽  
Ion Species ◽  
Two Fluid

AbstractWe characterise steady, one-dimensional fast and slow magnetohydrodynamic (MHD) shocks using a two-fluid model. Fast MHD shocks are magnetically driven, forcing ions to stream through the neutral gas ahead of the shock front. This magnetic precursor heats the gas sufficiently to create a large, warm transition zone where all fluid variables only weakly change in the shock front. In contrast, slow MHD shocks are driven by gas pressure where neutral species collide with ion species in a thin hot slab that closely resembles an ordinary gas dynamic shock.We computed observational diagnostics for fast and slow shocks at velocities vs=2–4 km/s and preshock Hydrogen nuclei densities nH = 102-4 cm−3. We followed the abundances of molecules relevant for a simple oxygen chemistry and include cooling by CO, H2 and H2O. Estimates of intensities of 12CO rotational lines show that high-J lines, above J = 6 → 5, are more strongly excited in slow MHD shocks.

scholarly journals Cascaded-Microrings Biosensors Fabricated on a Polymer Platform

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 181 ◽  
Author(s):  
Yuxin Liang ◽  
Qi Liu ◽  
Zhenlin Wu ◽  
Geert Morthier ◽  
Mingshan Zhao
Keyword(s):  
Free Spectral Range ◽  
Volume Ratio ◽  
Cost Effective ◽  
Spectral Shift ◽  
Microring Resonators ◽  
Optical Polymer ◽  
Peak Fitting ◽  
Fitting Method ◽  
Infrared Wavelengths ◽  
Vernier Effect

Polymer-based single-microring biosensors usually have a small free spectral range (FSR) that hampers the tracing of the spectrum shifting in the measurement. A cascade of two microring resonators based on the Vernier effect, is applied in this article in order to make up for this defect. A small FSR difference between the reference microring and the sensing microring is designed, in order to superpose the periodic envelope signal onto the constituent peaks, which makes it possible to continuously track the spectrum of the sensor. The optical polymer material, Ormocore, which has a large transparent window, is used in the fabrication. The biosensor is fabricated by using an UV-based soft imprint technique, which is considered to be cost-effective and suitable for mass production. By optimizing the volume ratio of Ormocore and the maT thinner, the device can be fabricated almost without a residual layer. The device works at a wavelength of 840 nm, where water absorption loss is much lower than at the infrared wavelengths. A two-step fitting method, including single-peak fitting and whole-envelope fitting, is applied in order to trace the spectral shift accurately. Finally, the two-cascaded-microrings biosensor is characterized, and the obtained FSR is 4.6 nm, which is 16 times larger than the FSR of the single microring biosensor demonstrated in our previous work. Moreover, the sensitivity can also be amplified by 16-fold, thanks to the Vernier effect.

scholarly journals Planetary magnetic field control of ion escape from weakly magnetized planets

2019 ◽  
Vol 488 (2) ◽  
pp. 2108-2120 ◽  
Author(s):  
Hilary Egan ◽  
Riku Jarvinen ◽  
Yingjuan Ma ◽  
David Brain
Keyword(s):  
Magnetic Field ◽  
Effective Interaction ◽  
Three Dimensional ◽  
Power Laws ◽  
Wind Pressure ◽  
Escape Rate ◽  
Opening Angle ◽  
Plasma Environment ◽  
Ion Escape ◽  
Planetary Magnetic Field

ABSTRACT Intrinsic magnetic fields have long been thought to shield planets from atmospheric erosion via stellar winds; however, the influence of the plasma environment on atmospheric escape is complex. Here we study the influence of a weak intrinsic dipolar planetary magnetic field on the plasma environment and subsequent ion escape from a Mars-sized planet in a global three-dimensional hybrid simulation. We find that increasing the strength of a planet’s magnetic field enhances ion escape until the magnetic dipole’s standoff distance reaches the induced magnetosphere boundary. After this point increasing the planetary magnetic field begins to inhibit ion escape. This reflects a balance between shielding of the Southern hemisphere from ‘misaligned’ ion pickup forces and trapping of escaping ions by an equatorial plasmasphere. Thus, the planetary magnetic field associated with the peak ion escape rate is critically dependent on the stellar wind pressure. Where possible we have fit power laws for the variation of fundamental parameters (escape rate, escape power, polar cap opening angle, and effective interaction area) with magnetic field, and assessed upper and lower limits for the relationships.

A new peak fitting method for 1D solid-state 29Si NMR spectra based on singular spectrum analysis

2019 ◽  
Vol 18 (01) ◽  
pp. 1941014
Author(s):  
Guiliang Li ◽  
Changjun Li ◽  
Nan Wei
Keyword(s):  
Molecular Structure ◽  
Spectrum Analysis ◽  
Nmr Spectra ◽  
Singular Spectrum Analysis ◽  
Embedding Dimension ◽  
Characteristic Peak ◽  
Gaussian Fitting ◽  
Singular Spectrum ◽  
Peak Fitting ◽  
Fitting Method

[Formula: see text]Si Nuclear Magnetic Resonance (NMR) can measure the molecular structure of silicate in oilfield reinjection water. However, noise in [Formula: see text]Si NMR spectra (NMRS) affects the determination of silicate molecular structure type. To solve this problem, a new peak fitting method (Two-step Greedy-Singular Spectrum Analysis-Gaussian Fitting Method, TSG-SSA-GFM) is proposed in this paper. This method first uses TSG to determine the embedding dimension, then uses SSA to determine the characteristic peak position. Finally, GFM is used to calculate the molar ratio of characteristic peaks. The results show that TSG can quickly determine the embedding dimension and reduce computation by at least 50% vs. the global ergodic method. The mean deviation of characteristic peak positions determined by SSA is 0.07 ppm, while Discrete Wavelet Transform (DWT) and Empirical Mode Decomposition (EMD) cannot determine characteristic peaks of [Formula: see text]Si NMRS containing overlapping peak. The average [Formula: see text]-squared of Gaussian fitting of [Formula: see text]Si NMRS is 98.4% while Lorentzian is 90.6%. Therefore, this study provides an important method for quantitative analysis of [Formula: see text]Si NMRS.

scholarly journals Studying Strangeness Production with HADES

2018 ◽  
Vol 171 ◽  
pp. 01001
Author(s):  
Heidi Schuldes
Keyword(s):  
Mass Spectra ◽  
Threshold Energy ◽  
Heavy Ion ◽  
Spectral Shape ◽  
Transverse Mass ◽  
Fixed Target ◽  
Fixed Target Experiments ◽  
Ion Collisions ◽  
Global Properties ◽  
The World

The High-Acceptance DiElectron Spectrometer (HADES) operates in the 1 - 2A GeV energy regime in fixed target experiments to explore baryon-rich strongly interacting matter in heavy-ion collisions at moderate temperatures with rare and penetrating probes. We present results on the production of strange hadrons below their respective NN threshold energy in Au+Au collisions at 1.23A GeV ([see formula in PDF] = 2.4 GeV). Special emphasis is put on the enhanced feed-down contribution of ϕ mesons to the inclusive yield of K- and its implication on the measured spectral shape of K-. Furthermore, we investigate global properties of the system, confronting the measured hadron yields and transverse mass spectra with a Statistical Hadronization Model (SHM) and a blastwave parameterization, respectively. These supplement the world data of the chemical and kinetic freeze-out temperatures.

scholarly journals Effects of the crustal magnetic fields on the Martian atmospheric ion escape rate

2016 ◽  
Vol 43 (20) ◽  
pp. 10,574-10,579 ◽  
Author(s):  
Robin Ramstad ◽  
Stas Barabash ◽  
Yoshifumi Futaana ◽  
Hans Nilsson ◽  
Mats Holmström
Keyword(s):  
Magnetic Fields ◽  
Escape Rate ◽  
Ion Escape
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