Ion Thermal Energy Research Articles

Behavior of Lithium Amide Under Argon Plasma.

Alkali and alkaline earth metal amides are a type of functional materials for hydrogen storage, thermal energy storage, ion conduction, and chemical transformations such as ammonia synthesis and decomposition. The thermal chemistry of lithium amide (LiNH2), as a simple but representative alkali or alkaline earth metal amide, has been well studied previously encouraged by its potentials in hydrogen storage. In comparison, little is known about the interaction of plasma and LiNH2. Herein, we report that the plasma treatment of LiNH2 in an Ar flow under ambient temperature and pressure gives rise to distinctly different reaction products and reaction pathway from that of the thermal process. We found that plasma treatment of LiNH2 leads to the formation of Li colloids, N2, and H2 as observed by UV-vis absorption, EPR, and gas products analysis. Inspired by this very unique interaction between plasma and LiNH2, a chemical loop for ammonia decomposition to N2 and H2 mediated by LiNH2 was proposed and demonstrated.

Spectromicroscopic study of the transformation with low energy ions of a hematite thin film into a magnetite/hematite epitaxial bilayer

The search of new properties in novel oxide heterostructures requires the exploration of new fabrication methods and the study, at the microscopic level, of the processes involved during the synthesis. We present a synchrotron-based spectromicroscopic investigation of a magnetite/hematite bilayer on Pt(111) grown in a two-step process by thermal evaporation and Low Energy Ion Bombardment (LEIB). The characterization includes the study of structural, electronic, chemical, and magnetic properties using X-ray Absorption Spectroscopy (XAS), Low Energy Electron Microscopy (LEEM), Photoemission Electron Microscopy (PEEM), or X-ray Magnetic Circular Dichroism (XMCD). The aim is to obtain microscopic information of the thin film before, during, and after the ion bombardment. Ion bombardment gradually transforms the topmost layers of the hematite thin film into a defective sub-oxide, where magnetite nuclei grow and coalesce with increasing ion doses. Two rotational domains of magnetite coexist, which are typically a few tens of nanometres large and do not grow significantly with temperature annealings. The incoherent growth of the magnetite nuclei favours the formation of stable twin boundaries (TBs) and antiphase boundaries (APBs). Dichroic spectra show the characteristics of the ferrimagnetic (FiM) order of magnetite, and the spatial distribution of magnetic domains shows no apparent correlation with the structural image, displaying smooth domains separated by diffuse frontiers. These findings illustrate the importance of a spectromicroscopic characterization of novel oxide heterostructures for potential future applications.

The azimuthal currents in the ion-driven magnetic nozzle

Ion-driven magnetic nozzles (Ti > Te) are designed as intrinsic parts of cutting-edge propulsive technologies such as variable specific impulse magnetoplasma rockets (VASIMRs) and applied-field magnetoplasmadynamic thrusters. Employing a two-dimensional axisymmetric particle-in-cell (PIC) code, in the ion-driven magnetic nozzle, the compositions and distributions of azimuthal currents in different axial regions are investigated under various inlet ion temperatures Ti0 and found to differ dramatically from that in the electron-driven magnetic nozzles. Previously reported to be all paramagnetic and vanishing under a high magnetic field, the azimuthal currents resulting from the E × B drift are shown to turn diamagnetic and sustain a considerable magnitude when Ti0 is considered. The previously reported profile of diamagnetic drift current is altered by the introduction of inlet ion temperature, and the paramagnetic part is significantly suppressed. Moreover, a wide range of paramagnetic currents appear downstream due to the inward detachment of ions, which can also be reduced by increasing inlet ion temperature. Albeit considered in this paper, the azimuthal currents resulting from grad-B and curvature drift are still negligible in all cases of interest. The magnitude of diamagnetic azimuthal currents increases with amplifying Ti0, indicating a clear physical image of energy transformation from ion thermal energy to the directed kinetic energy through electromagnetic processes in the magnetic nozzle. Additionally, the magnetic inductive strength also has noticeable impacts on the azimuthal currents, the current magnitude tends to decrease as the magnetic field increases, and over-increment of it may result in larger divergence angles and lower nozzle efficiency.

Confinement properties of L-mode plasmas in ASDEX Upgrade and full-radius predictions of the TGLF transport model

The properties of L-mode confinement have been investigated with a set of dedicated experiments in ASDEX Upgrade and with a related modelling activity with the transport code ASTRA and the quasi-linear turbulent transport model TGLF–SAT2, with boundary conditions at the separatrix. The values at the boundary have been set by the two-point model for the electron temperature, with the ion temperature proportional to the electron temperature by a constant factor, and the electron density set by a constant fraction of the volume averaged density. The influx of neutrals has been set through a feedback procedure which ensures that in the simulation the same particle content as in the experiment is obtained. The sensitivity of the results under considerable variations in the choice of the boundary conditions has been investigated and found to be limited. The predictions of this full-radius modelling set-up have been compared to experimental results covering a scan in electron cyclotron resonance heating (ECRH) power in both hydrogen and deuterium plasmas, a plasma current scan with fixed magnetic field, under both ECRH and neutral beam injection heating, an increase in plasma density with constant ECRH power in hydrogen plasmas, as well as variations of the fraction of electron and ion heating at approximately constant total heating power, as well as a change of main ion from deuterium to hydrogen. The ASTRA-TGLF predictions have been found to reproduce all of the experimentally explored dependences with relatively good accuracy, providing evidence, for the first time to our knowledge, that the main properties of L-mode confinement can be reproduced by conventional full-radius transport modelling with a quasi-linear turbulent transport model. Evidences of largest disagreement, although usually not exceeding the 20%, have been found at high electron heating power, where TGLF underpredicts the electron and particularly the ion thermal stored energies, and in the current dependence of confinement, which, in electron heated conditions, is predicted to be weaker than in the experiment.

Enhanced performance of a direct contact membrane distillation system via in-situ thermally activated H2O2 oxidation for the treatment of landfill leachate

In this study, an integrated system of self-enhanced membrane distillation (MD) with H2O2 oxidation was explored for the efficient treatment of landfill leachate, in which the heat energy required for MD operation was harvested for H2O2 activation. Organic composition of the leachate was explored during the filtration processes via fluorescence excitation emission matrix combined with parallel factor analysis, which identified three different organic fractions (i.e., tryptophan-like C1, fulvic-like C2, and humic-like C3) in the extracted membrane foulants as well as in the membrane concentrate. C1 was the main organic fraction in the foulant, while C3 was dominant in the leachate concentrate. Moreover, H2O2 was successfully activated by the in situ thermal energy (i.e., temperature difference) and pristine Fe ions in the leachate, resulting in significant (48%) oxidation of bulk organic matter. Preferential removal of the main fouling fraction (i.e., C1) from the bulk landfill leachate occurred under the optimal H2O2 dose of 1.5 g/L. With respect to the H2O2 dose on the feed side of the assisted MD setup, there was a considerable increase in the membrane flux, a 24% higher membrane flux recovery, and 1.5 times more filtered volume, as compared to the reference run without oxidation. The addition of H2O2 to the conventional MD also led to a significant (93%) removal of the bio-refractory humic-like C3 fraction from the membrane concentrate. The results of this study demonstrated the successful operation of assisted MD based on the in-situ energy utilization for H2O2 activation, which led to a drastic improvement in the performance of the system and the production of low-strength, reclaimable leachate concentrate.

Ion versus Electron Heating in Compressively Driven Astrophysical Gyrokinetic Turbulence

The partition of irreversible heating between ions and electrons in compressively driven (but subsonic) collisionless turbulence is investigated by means of nonlinear hybrid gyrokinetic simulations. We derive a prescription for the ion-to-electron heating ratio $Q_\rmi/Q_\rme$ as a function of the compressive-to-Alfv\'enic driving power ratio $P_\compr/P_\AW$, of the ratio of ion thermal pressure to magnetic pressure $\beta_\rmi$, and of the ratio of ion-to-electron background temperatures $T_\rmi/T_\rme$. It is shown that $Q_\rmi/Q_\rme$ is an increasing function of $P_\compr/P_\AW$. When the compressive driving is sufficiently large, $Q_\rmi/Q_\rme$ approaches $\simeq P_\compr/P_\AW$. This indicates that, in turbulence with large compressive fluctuations, the partition of heating is decided at the injection scales, rather than at kinetic scales. Analysis of phase-space spectra shows that the energy transfer from inertial-range compressive fluctuations to sub-Larmor-scale kinetic Alfv\'en waves is absent for both low and high $\beta_\rmi$, meaning that the compressive driving is directly connected to the ion entropy fluctuations, which are converted into ion thermal energy. This result suggests that preferential electron heating is a very special case requiring low $\beta_\rmi$ and no, or weak, compressive driving. Our heating prescription has wide-ranging applications, including to the solar wind and to hot accretion disks such as M87 and Sgr A*.

Energy Conversion between Ions and Electrons through Ion Cyclotron Waves and Embedded Ion-scale Rotational Discontinuity in Collisionless Space Plasmas

Abstract Wave–particle interaction is a fundamental process in collisionless plasma, which results in the redistribution of energy between plasma waves and particle species. The analysis of high-resolution Magnetospheric Multiscale plasma and magnetic field data directly reveals the energy exchange between electromagnetic energy, particle bulk kinetic energy, and thermal kinetic energy in magnetosheath turbulence. This work focuses on the energy transfer associated with ion cyclotron waves (ICWs) and embedded rotational discontinuity (RD). We find that (1) the particle kinetic energy of ions is converted into electromagnetic energy; (2) the electrons are gaining energy from electromagnetic fields, having significant electron heating in the parallel direction around the RD; (3) the ICWs and RD connect and redistribute energy between ions and electrons in the postshock downstream sheath region; and (4) the interactions between pressure tensor and strain tensor redistribute the ion and electron bulk and thermal kinetic energies, but less significantly than direct field–particle interaction by one order of magnitude in the ICW turbulence with weak compressibility, in the sense that , .

Electric potential barriers in the magnetic nozzle.

Magnetic nozzles are convergent-divergent applied magnetic fields which are commonly used in electric propulsion, manufacturing, and material processing industries. This paper studies the previously overlooked physics in confining the thermalized ions injected from a near-uniform inlet in the magnetic nozzle. Through fully kinetic planar-3V particle-in-cell (PIC) modeling and simulation, an electric potential barrier is found on the periphery of the nozzle throat, which serves to confine the thermalized ions by the electric force. With the initial thermal energy as driving force and insufficient magnetic confinement, the ions overshoot the most divergent magnetic line, which results in the accumulation of positive space charges around the throat. The accumulated charges would create an ion-confining potential barrier with limited extent. Apart from the finite-electron Larmor radius (FELR) effect, two more factors are put forward to account for the limited extent of the potential barrier: the depletion of ion thermal energy and the short-circuiting effect. The influences of inlet temperature ratio of ions to electrons and magnetic inductive strength B_{0} are quantitively investigated using the PIC code. The results indicate that the potential barrier serves as a medium to transfer the gas dynamic thrust to the magnetic nozzle while providing constrain to the ions, like the solid wall in a de Laval nozzle. In high-B_{0} regime, the finite-ion Larmor radius (FILR) effect becomes dominant rather than the FELR effect in the plasma confinement of magnetic nozzles.

Particle simulation studies of merging processes of two spherical-tokamak-type plasmoids

The merging processes of spherical-tokamak-type plasmoids (STs), which are confined in a rectangular conducting vessel, are investigated by means of a two-dimensional particle-in-cell simulation. A series of simulation runs with different mass ratios clarify that a starting time of the ST merging is nearly given by a transit time for an ion sound wave to travel from an inner edge of each ST in an initial profile to a reconnection point and a part of poloidal magnetic energy is transferred to the ion thermal energy and the electron thermal energy at the approximate rate of 3:1 during the ST merging process, which is almost independent of the mass ratio except for the smallest mass ratio case of (Mi/Me) = 100. This transfer process leads to the increases in a parallel component of electron temperature and a perpendicular component of ion temperature while keeping the other components almost constant. This is because the two-component electron distribution function with different velocity shifts along a toroidal magnetic field is formed around a reconnection point when two STs merge. On the other hand, an ion distribution function, consisting of three components with different velocity shifts perpendicular to the toroidal magnetic field, is formed around the reconnection point in the merging phase. It is also found that a sharp peak appears impulsively in the electron parallel temperature profile in the merging phase, which is consistent with the Mega Ampere Spherical Tokamak merging experiments [H. Tanabe et al., Nucl. Fusion 57, 056037 (2017)].

Thick CrN/AlN superlattice coatings deposited by hot filament assisted HiPIMS for solid particle erosion and high temperature wear resistance

There are needs for the development of advanced ceramic coatings for industrial applications, e.g. die casting dies, forming tools, injection molds, valves in oil and gas field, etc. In many cases, under very severe working environment when high pressure and high velocity solid particle erosion and/or wear at high temperatures are involved, traditional hard coatings with thickness of several micrometers may not be satisfactory. High quality thick ceramic coatings are needed to achieve improved durability and performance. In this study, CrN/AlN thick superlattice coatings with thickness up to 20 μm were deposited on stainless steel and WC-Co substrates by reactive high power impulse magnetron sputtering (HiPIMS) combined with hot filament plasma assistance. The coatings were deposited at different hot filament plasma currents (ID), which correlate to different levels of ion fluxes and thermal energies superimposed on growing coatings. The bilayer thickness of these thick CrN/AlN coatings is in the range of 5.4 to 6.7 nm. The microstructure of the coatings gradually changes from loose cone-shaped columnar grains to extremely dense fine columnar grains with increasing ID. These thick CrN/AlN coatings show excellent adhesion and crack resistance with a maximum micro hardness up to 3800 Hv. The solid particle erosion resistance of the coatings was evaluated using an air jet sand erosion tester. The high temperature wear resistance of the coating was measured using a high temperature pin-on-disc tribometer in the ambient air from 600 °C to 1000 °C. It has shown that the hot filament plasma provides greatly enhanced ion flux bombardment and thermal energies, which are critical for obtaining consistent dense structure and fine grains for thick ceramic coating growth.

Floating potential calculation for a Langmuir probe in electronegative plasmas and experimental validation in a glow discharge

A radial Langmuir probe sheath model is used to make a prediction of the floating potential of a Langmuir probe immersed in an electronegative plasma. The new electronegative plasma sheath model takes into account the positive ion and the negative ion thermal energies and is valid for any ion temperature value. The values predicted can be used for diagnosing and controlling an electronegative plasma, and we compare them with measurements of the floating potential in an Argon plasma and in a Neon plasma with with two distinct electron populations at different temperatures. We have found that the agreement is very good in a wide range of plasma pressure and discharge current values, and thus the model is applicable for electronegative plasmas. Moreover, the model can be used to measure the energy with which the ions will collide with the surface of the probe.

Stochastic Ion Acceleration by the Ion-cyclotron Instability in a Growing Magnetic Field

Abstract Using 1D and 2D particle-in-cell simulations of a plasma with a growing magnetic field , we show that ions can be stochastically accelerated by the ion-cyclotron (IC) instability. As grows, an ion pressure anisotropy arises due to the adiabatic invariance of the ion magnetic moment ( and p ⊥,i are the ion pressures parallel and perpendicular to ). When initially β i = 0.5 ( , where p i is the ion isotropic pressure), the pressure anisotropy is limited mainly by inelastic pitch-angle scattering provided by the IC instability, which in turn produces a nonthermal tail in the ion energy spectrum. After is amplified by a factor of ∼2.7, this tail can be approximated as a power law of index ∼3.4 plus two nonthermal bumps and accounts for 2%–3% of the ions and ∼18% of their kinetic energy. On the contrary, when initially β i = 2, the ion scattering is dominated by the mirror instability, and the acceleration is suppressed. This implies that efficient ion acceleration requires that initially, β i ≲ 1. Although we focus on cases where is amplified by plasma shear, we check that the acceleration occurs similarly if grows due to plasma compression. Our results are valid in a subrelativistic regime where the ion thermal energy is ∼10% of the ion rest-mass energy. This acceleration process can thus be relevant in the inner region of low-luminosity accretion flows around black holes.

Determination of the Ion Temperature in a High-Energy-Density Plasma Using the Stark Effect.

We present the experimental determination of the ion temperature in a neon-puff Z pinch. The diagnostic method is based on the effect of ion coupling on the Stark line shapes. It was found, in a profoundly explicit way, that at stagnation the ion thermal energy is small compared to the imploding-plasma kinetic energy, where most of the latter is converted to hydromotion. The method here described can be applied to other highly nonuniform and transient high-energy-density plasmas.

Study of Electromagnetic Electron Cyclotron Waves for Kappa Distribution with AC Field in the Magnetosphere of Saturn

Parallel propagating electromagnetic electron cyclotron (EMEC) waves in the extended plasma sheet (~12RS) and in the outer magnetosphere (~18RS) of Saturn have been studied. A dispersion relation for parallel propagating relativistic EMEC waves has been applied to the magnetosphere of Saturn, and comparisons have been made with the data of Voyager 1 at these radial distances. The detailed investigations for EMEC waves have been done in the presence of the perpendicular AC electric field, using the kappa distribution function. The relativistic temporal growth rate is calculated by the method of characteristic solution with the data provided by Voyager 1. The effect of the suprathermal electron density, temperature anisotropy, frequency of AC electric field, thermal energy of ions, and relativistic factor on the temporal growth rate of EMEC wave emission has been studied. The simulation results show that the growth of parallel propagating EMEC waves is significantly affected by variations in the temperature anisotropy, electron density, ion thermal energy, and relativistic factor in both the extended plasma sheet and the outer magnetosphere of Saturn. The temperature anisotropy (T⊥/T║), ion thermal energy (KBT║i), and electron density (n0) have been found to be a major source of free energy for parallel propagating EMEC waves in both regions.

(Invited) Fundamentals and Applications of Directional and Isotropic Atomic Layer Etching

Atomic Layer Etching (ALE) is a cyclic process comprised of a self-limited surface modification step followed by a self-limited step to remove the modified layer. Based on this definition, there are several approaches to realize and classify ALE. For instance, one can distinguish between directional and isotropic ALE depending on whether the removal of the activated layer is accomplished by ion bombardment or thermal energy. Thanks to such salient performance benefits as uniformity across all length scales and selectivity, atomic layer etching is being proliferated in production. Directional ALE was the first process to go into production because most critical etch applications require directionality. Isotropic ALE is an emerging branch based on chemical reactions akin to those uses in thermal ALD. The term “isotropic” means that the etch proceeds in all directions. This property is particularly valued in vertical device integration where materials need to be removed from vertical and concealed surfaces. In this talk, a conceptual framework for directional and isotropic ALE will be introduced to explain the performance benefits and limitations of both technologies. Experimental and theoretical results as well as applications examples will be presented to illustrate the concepts.

Analysis of dayside magnetosphere of Mars: High mass loading case as observed on MAVEN spacecraft

MAVEN spacecraft provides new opportunities for analysis of Martian environment and physical process in near-Mars space. One of interesting regions of near-Mars space is the Martian magnetosphere that is formed from mass-loaded magnetic flux tubes. There is quite detailed knowledge of the night-side magnetosphere of Mars, however the number of publications on the dayside magnetosphere are quite limited. We analyze the plasma and magnetic structure and properties of Martian magnetosphere at strong mass-loading conditions as observed on MAVEN at Mars at the solar-zenith angle of ∼80° on January 4, 2015. This strong mass loading of upstream flow was apparently associated with plume ions ejected from upper part of Martian magnetosphere by the solar wind motional electric field. The magnetosphere is defined by two current layers separating it from the magnetosheath at higher altitudes and from ionosphere plasma at lower altitudes. It is characterized by dominance of planetary ions which number density increases by two orders of magnitude from upper boundary to lower one. There is approximate equipartition between magnetic, ion thermal and kinetic energies through magnetosphere. The data suggest that the boundary of the magnetosphere is in pressure equilibrium with magnetosheath flow. The total energy of ion flow above (in the magnetosheath) and below (in the region of accelerated ionospheric ions) magnetosphere exceeds the magnetic energy. The upper boundary of magnetosphere was located at the place where the ratio of heavy ions and protons number densities reached ∼0.4. Within magnetosphere this ratio continued to rise and increased by about 2 orders of magnitude at the inner boundary of magnetosphere. The heavy ion number density profile within magnetosphere suggests that it was formed by the solar wind magnetic flux tubes that reached Mars in a narrow region near the subsolar point, and then drifted around Mars to the terminator region, mass-loaded by UV-ionized upper atmosphere neutrals during this drift.

An improved and fully implicit multi-group non-local electron transport model and its validations

The combined effect of thermal flux inhibition and non-local electron heat flux in the radiation hydrodynamics (RHD) simulation of laser-driven systems can be accurately predicted by using non-local electron transport (NLET) models. These models can avoid commonly used space and time-independent ad-hoc flux-limiting procedures. However, the use of classical electron collision frequency in these models is rigorously valid for high temperature non-degenerate plasmas. In laser-driven systems, the electron thermal energy transport is important in regions between the critical density and ablation surface where the plasma is partially degenerate. Therefore, an improved model for electron collision frequency in this regime is required to accurately predict the thermal energy transport. Previously, we have reported an improved single group non-local electron transport model by using a wide-range electron collision frequency model valid from warm-dense matter (WDM) to fully ionized plasmas. In this work, we have extended this idea into a two-dimensional multi-group non-local electron transport (MG-NLET) model. Moreover, we have used a fully implicit numerical integration scheme in which the models for multi-group thermal radiation transport, laser absorption, electron-ion thermal energy relaxation and ion heat conduction are included in a single step. The performance of this improved MG-NLET model has been assessed by comparing the simulated foil trajectories with the reported experimental data for laser-driven plastic foils. The results indicate that the improved model yields results that are in better agreement with the experimental data.

Localized electron heating during magnetic reconnection in MAST

Significant increase in the plasma temperature above 1 keV was measured during the kilogauss magnetic field reconnection of two merging toroidal plasmas under the high-guide field and collision-less conditions. The electron temperature was observed to peak significantly at the X-point inside the current sheet, indicating Joule heating caused by the toroidal electric field along the X-line. This peaked temperature increases significantly with the guide field, in agreement with the electron mean-free path calculation. The slow electron heating in the downstream suggests energy conversion from ions to electrons through ion-electron collisions in the bulk plasma as the second electron heating mechanism in the bulk plasma. The electron density profile clearly reveals the electron density pile-up / fast shock structures in the downstream of reconnection, suggesting energy conversion from ion flow energy to ion thermal energy as well as significant ion heating by reconnection outflow.

Non-modal theory of the kinetic ion temperature gradient driven instability of plasma shear flows across the magnetic field

The temporal evolution of the kinetic ion temperature gradient driven instability and of the related anomalous transport of the ion thermal energy of plasma shear flow across the magnetic field is investigated analytically. This instability develops in a steady plasma due to the inverse ion Landau damping and has the growth rate of the order of the frequency when the ion temperature is equal to or above the electron temperature. The investigation is performed employing the non-modal methodology of the shearing modes which are the waves that have a static spatial structure in the frame of the background flow. The solution of the governing linear integral equation for the perturbed potential displays that the instability experiences the non-modal temporal evolution in the shearing flow during which the unstable perturbation becomes very different from a canonical modal form. It transforms into the non-modal structure with vanishing frequency and growth rate with time. The obtained solution of the nonlinear integral equation, which accounts for the random scattering of the angle of the ion gyro-motion due to the interaction of ions with ensemble of shearing waves, reveals similar but accelerated process of the transformations of the perturbations into the zero frequency structures. It was obtained that in the shear flow the anomalous ion thermal conductivity decays with time. It is a strictly non-modal effect, which originates from the temporal evolution of the shearing modes turbulence.

Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions

“Reduced” (i.e., simplified or approximate) ion-kinetic (RIK) models in radiation-hydrodynamic simulations permit a useful description of inertial-confinement-fusion (ICF) implosions where kinetic deviations from hydrodynamic behavior are important. For implosions in or near the kinetic regime (i.e., when ion mean free paths are comparable to the capsule size), simulations using a RIK model give a detailed picture of the time- and space-dependent structure of imploding capsules, allow an assessment of the relative importance of various kinetic processes during the implosion, enable explanations of past and current observations, and permit predictions of the results of future experiments. The RIK simulation method described here uses moment-based reduced kinetic models for transport of mass, momentum, and energy by long-mean-free-path ions, a model for the decrease of fusion reactivity owing to the associated modification of the ion distribution function, and a model of hydrodynamic turbulent mixing. The transport models are based on local gradient-diffusion approximations for the transport of moments of the ion distribution functions, with coefficients to impose flux limiting or account for transport modification. After calibration against a reference set of ICF implosions spanning the hydrodynamic-to-kinetic transition, the method has useful, quantifiable predictive ability over a broad range of capsule parameter space. Calibrated RIK simulations show that an important contributor to ion species separation in ICF capsule implosions is the preferential flux of longer-mean-free-path species out of the fuel and into the shell, leaving the fuel relatively enriched in species with shorter mean free paths. Also, the transport of ion thermal energy is enhanced in the kinetic regime, causing the fuel region to have a more uniform, lower ion temperature, extending over a larger volume, than implied by clean simulations. We expect that the success of our simple approach will motivate continued theoretical research into the development of first-principles-based, comprehensive, self-consistent, yet useable models of kinetic multispecies ion behavior in ICF plasmas.