Showing papers by "Princeton Plasma Physics Laboratory published in 2022"

Afterslip Moment Scaling and Variability From a Global Compilation of Estimates

Abstract: Aseismic afterslip is postseismic fault sliding that may significantly redistribute crustal stresses and drive aftershock sequences. Afterslip is typically modeled through geodetic observations of surface deformation on a case-by-case basis, thus questions of how and why the afterslip moment varies between earthquakes remain largely unaddressed. We compile 148 afterslip studies following 53 Mw6.0–9.1 earthquakes, and formally analyze a subset of 88 well-constrained kinematic models. Afterslip and coseismic moments scale near-linearly, with a median Spearman's rank correlation coefficient (CC) of 0.91 after bootstrapping (95% range: 0.89–0.93). We infer that afterslip area and average slip scale with coseismic moment as and , respectively. The ratio of afterslip to coseismic moment (Mrel) varies from <1% to >300% (interquartile range: 9%–32%). Mrel weakly correlates with Mo (CC: −0.21, attributed to a publication bias), rupture aspect ratio (CC: −0.31), and fault slip rate (CC: 0.26, treated as a proxy for fault maturity), indicating that these factors affect afterslip. Mrel does not correlate with mainshock dip, rake, or depth. Given the power-law decay of afterslip, we expected studies that started earlier and spanned longer timescales to capture more afterslip, but Mrel does not correlate with observation start time or duration. Because Mrel estimates for a single earthquake can vary by an order of magnitude, we propose that modeling uncertainty currently presents a challenge for systematic afterslip analysis. Standardizing modeling practices may improve model comparability, and eventually allow for predictive afterslip models that account for mainshock and fault zone factors to be incorporated into aftershock hazard models.

A new clade 2.3.4.4b H5N1 highly pathogenic avian influenza genotype detected in Europe in 2021

Abstract: Despite their widespread distribution, only a single genotype variant of clade 2.3.4.4b H5N1 influenza viruses has been found so far in Europe. Here, we report the detection of a new highly pathogenic avian influenza H5N1 genotype in geese and ducks from a backyard farm in the Czech Republic. Phylogenetic analysis revealed that the Czech H5N1 virus retained the A/Eurasian_Wigeon/Netherlands/1/2020-like backbone with an altered PB2 segment obtained from co-circulating low-pathogenic avian influenza viruses.

The dispersion and propagation of topological Langmuir-cyclotron waves in cold magnetized plasmas

Abstract: Topological Langmuir-Cyclotron Wave (TLCW) is a recently identified topological surface excitation in magnetized plasmas. We show that TLCW originates from the topological phase transition at the Langmuir wave-cyclotron wave resonance. By isofrequency surface analysis and 2D and 3D time-dependent simulations, we demonstrate that the TLCW can propagate robustly along complex phase transition interfaces in a unidirectional manner and without scattering. Because of these desirable features, the TLCW could be explored as an effective mechanism to drive current and flow in magnetized plasmas. The analysis also establishes a close connection between the newly instituted topological phase classification of plasmas and the classical CMA diagram of plasma waves.

Role of Collagen in Vascular Calcification

Abstract: Vascular calcification is a pathological process characterized by ectopic calcification of the vascular wall. Medial calcifications are most often associated with kidney disease, diabetes, hypertension, and advanced age. Intimal calcifications are associated with atherosclerosis. Collagen can regulate mineralization by binding to apatite minerals and promoting their deposition, binding to collagen receptors to initiate signal transduction, and inducing cell transdifferentiation. In the process of vascular calcification, type I collagen is not only the scaffold for mineral deposition but also a signal entity, guiding the distribution, aggregation, and nucleation of vesicles and promoting the transformation of vascular smooth muscle cells into osteochondral-like cells. In recent years, collagen has been shown to affect vascular calcification through collagen disc-domain receptors, matrix vesicles, and transdifferentiation of vascular smooth muscle cells.

Internal rotation of ELM filaments on NSTX

Abstract: Edge localized modes (ELMs) are a threat to tokamaks due to their high heat and particle loads on plasma facing components. A significant portion of this energy is carried and deposited by the emerging ELM filaments, whose dynamics are directly connected to their impact. Therefore, understanding their underlying physics is important for the operation of future fusion reactors. Our paper extends our knowledge of ELM filaments by reporting on their internal rotation (spinning) around the magnetic field lines along which they are extended. Our analysis of gas-puff imaging data on National Spherical Torus Experiment shows that ELM filaments are characterized by internal rotation in the direction of the ion-gyromotion with [Formula: see text] median angular velocity, which is approximately three times faster than the blob rotation in the background turbulence. The characteristic size of the ELM filament was also assessed and found to be similar to the blobs. A nearly linear trend was found between the angular velocity and the radial velocity of the ELM filament. The angular velocity was found to be linearly dependent on the distance of the filament from the separatrix, as well. An analytical model called the shear-induced rotation model was identified as a candidate for explaining the physics of the observations. Our results show that the modeled mechanism could significantly influence the rotation of the ELM filament; however, it cannot be a sole contributor.

Relative Afterslip Moment Does Not Correlate With Aftershock Productivity: Implications for the Relationship Between Afterslip and Aftershocks

Abstract: Aseismic afterslip has been proposed to drive aftershock sequences. Both afterslip moment and aftershock number broadly increase with mainshock size, but can vary beyond this scaling. We examine whether relative afterslip moment (afterslip moment/mainshock moment) correlates with several key aftershock sequence characteristics, including aftershock number and cumulative moment (both absolute and relative to mainshock size), seismicity rate change, b-value, and Omori decay exponent. We select Mw ≥ 4.5 aftershocks for 41 tectonically varied mainshocks with available afterslip models. Against expectation, relative afterslip moment does not correlate with tested aftershock characteristics or background seismicity rate. Furthermore, adding afterslip moment to mainshock moment does not improve predictions of aftershock number. Our findings place useful empirical constraints on the link between afterslip and potentially damaging Mw ≥ 4.5 aftershocks and raise questions regarding the role afterslip plays in aftershock generation.

Highly Site‐ and Enantioselective N—H Functionalization of <scp> <i>N</i> ‐Monosubstituted </scp> Aniline Derivatives Affording Pyrazolones Bearing a Quaternary Stereocenter

Abstract: Chiral phosphoric acid catalyzed the regio- and enantioselective N—H functionalization of N-alkylaniline with pyrazolones derived ketimines as electrophiles, providing a variety of chiral pyrazolones containing a tetrasubstituted stereocenter bearing a new N,N’-acetal motif in excellent yields and high enantioselectivities. This strategy was featured by low catalyst loading, mild conditions, and high efficiency and selectivity. Appendix S1: Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Finite orbit width effects in large aspect ratio stellarators

Abstract: New orbit-averaged equations for low collisionality neoclassical fluxes in large aspect ratio stellarators with mirror ratios close to unity are derived. The equations retain finite orbit width effects by employing the second adiabatic invariant $J$ as a velocity-space coordinate and they have been implemented in the orbit-averaged neoclassical code KNOSOS (Velasco et al. , J. Comput. Phys. , vol. 418, 2020, 109512; Velasco et al. , Nucl. Fusion , vol. 61, 2021, 116013). The equations are used to study the $1/ u$ regime and the lower collisionality regimes. For generic large aspect ratio stellarators with mirror ratios close to unity, as the collision frequency decreases, the $1/ u$ regime transitions directly into the $ u$ regime, without passing through a $\sqrt { u }$ regime. An explicit formula for the neoclassical fluxes in the $ u$ regime is obtained. The formula includes the effect of particles that transition between different types of wells. While these transitions produce stochastic scattering independent of the value of the collision frequency in velocity space, the diffusion in real space remains proportional to the collision frequency. The $\sqrt { u }$ regime is only recovered in large aspect ratio stellarators close to omnigeneity: large aspect ratio stellarators with large mirror ratios and optimized large aspect ratio stellarators with mirror ratios close to unity. Neoclassical transport in large aspect ratio stellarators with large mirror ratios can be calculated with the orbit-averaged equations derived by Calvo et al. ( Plasma Phys. Control. Fusion , vol. 59, 2017, 055014). In these stellarators, the $\sqrt { u }$ regime exists in the collisionality interval $(a/R) \ln (R/a) \ll u _{ii} R a/\rho _i v_{ti} \ll R/a$ . In optimized large aspect ratio stellarators with mirror ratios close to unity, the $\sqrt { u }$ regime occurs in an interval of collisionality that depends on the deviation from omnigeneity $\delta$ : $\delta ^{2} |\ln \delta | \ll u _{ii} R a/\rho _i v_{ti} \ll 1$ . Here, $ u _{ii}$ is the ion–ion collision frequency, $\rho _i$ and $v_{ti}$ are the ion gyroradius and thermal speed, and $a$ and $R$ are the minor and major radii.

Designing Color-tunable luminescent thermometers and information encryption based on Pr3+ or Sm3+ doped SrNb2O6: Tb3+ phosphors via energy transfer

Abstract: Color-tunable luminescence intensity ratio thermometers and information encryption are firstly designed through different energy transfer mechanism. Herein, two types thermometric materials, SrNb2O6: Tb3+, Pr3+ and SrNb2O6: Tb3+, Sm3+ are prepared. The Tb3+ and Pr3+ typical emissions show luminescence mechanism between two intervalence charge transfer states. Whereas, Tb3+ and Sm3+ emissions are related to energy migration from intervalence charge transfer state to 4f level. Interestingly, (5D4→7F5)Tb3+/(1D2→3H4)Pr3+ or (5D4→7F5)Tb3+/(4G5/2→6H7/2)Sm3+ have different temperature sensing properties due to distinct energy transfer processes and provide visualization of temperature measurement. The former gains high sensitivity (Sa = 0.012 K−1) at high temperature region, and the latter reach as high as Sa = 0.028 K−1 at low temperature. Besides, using multi-mode color emission of Tb3+ or Pr3+ doped SrNb2O6 achieves information hiding. This work not only shows new strategy to develop high-efficiency luminescent thermometers but also develop flexible optical encryption technology.

Europa Clipper Mission Update

Abstract: &lt;p&gt;With a launch readiness date of late 2024, NASA&amp;#8217;s Europa Clipper will set out on a journey to explore the habitability of Jupiter&amp;#8217;s moon Europa. At the beginning of the next decade, the spacecraft will orbit Jupiter, flying by Europa more than 40 times over a four-year period to observe this moon&amp;#8217;s ice shell and ocean, study its composition, investigate its geology, and search for and characterize any current activity. The mission&amp;#8217;s science objectives will be accomplished using a highly capable suite of remote-sensing and in-situ instruments. The remote sensing payload consists of the Europa Ultraviolet Spectrograph (Europa-UVS), the Europa Imaging System (EIS), the Mapping Imaging Spectrometer for Europa (MISE), the Europa Thermal Imaging System (E-THEMIS), and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The in-situ instruments comprise the Europa Clipper Magnetometer (ECM), the Plasma Instrument for Magnetic Sounding (PIMS), the SUrface Dust Analyzer (SUDA), and the MAss Spectrometer for Planetary Exploration (MASPEX). Gravity and radio science will be achieved using the spacecraft's telecommunication system, and valuable scientific data will be acquired by the spacecraft&amp;#8217;s radiation monitoring system. Major milestones from the past year include selection of a launch vehicle and launch readiness date by NASA, evaluation of candidate tours by the science team, and preparations for the cruise and operational phases of the mission. The project, flight system, and payload have completed their Critical Design Reviews, and the mission has recently completed its System Integration Review. Spacecraft subsystems and payload are actively being developed, and assembly, test, and launch operations are expected to begin in March 2022. In the meantime, the science team is preparing a set of manuscripts describing the mission science and the instruments that enable these investigations for publication in the journal Space Science Reviews.&lt;/p&gt;

Triggering tearing in a forming current sheet with the mirror instability

Abstract: We study the time-dependent formation and evolution of a current sheet (CS) in a magnetised, collisionless, high-beta plasma using hybrid-kinetic particle-in-cell simulations. An initially tearing-stable Harris sheet is frozen into a persistently driven incompressible flow so that its characteristic thickness gradually decreases in time. As the CS thins, the strength of the reconnecting field increases, and adiabatic invariance in the inflowing fluid elements produces a field-biased pressure anisotropy with excess perpendicular pressure. At large plasma beta, this anisotropy excites the mirror instability, which deforms the reconnecting field on ion-Larmor scales and dramatically reduces the effective thickness of the CS. Tearing modes whose wavelengths are comparable to that of the mirrors then become unstable, triggering reconnection on smaller scales and at earlier times than would have occurred if the thinning CS were to have retained its Harris profile. A novel method for identifying and tracking X-points is introduced, yielding X-point separations that are initially intermediate between the perpendicular and parallel mirror wavelengths in the upstream plasma. These mirror-stimulated tearing modes ultimately grow and merge to produce island widths comparable to the CS thickness, an outcome we verify across a range of CS formation timescales and initial CS widths. Our results may find their most immediate application in the tearing disruption of magnetic folds generated by turbulent dynamo in weakly collisional, high-beta, astrophysical plasmas.

The Beaufort Gyre’s Diffusive Staircase: Finescale Signatures of Gyre‐Scale Transport

Abstract: Arctic Ocean waters sourced from the Atlantic contain a vast amount of heat. In the Arctic’s Beaufort Gyre, diffusive convection is the primary mechanism by which this heat is transported vertically. This mixing process is characterized by a “staircase” where convective layers are separated by interfaces in temperature and salinity. It is not well-understood what governs layer thickness, which is an important parameter in heat transport. Here we relate staircase properties to the background water-mass structure of the Beaufort Gyre via analysis of Ice-Tethered Profiler observations. We find that staircase layer thicknesses vary with intrusive features below the staircase and the stratification overlying the staircase. We relate these features to the pathway of anomalously warm Atlantic Water in the Beaufort Gyre. Results suggest that intrusive features in context with the Gyre’s large-scale geostrophic flow may be key to understanding layer thicknesses and the propagation of warm waters into the Gyre.

Radial Interplanetary Magnetic Field‐Induced North‐South Asymmetry in the Solar Wind‐Magnetosphere‐Ionosphere Coupling: A Case Study

Abstract: In this paper, we present a case study of the radial interplanetary magnetic field (IMF Bx)-induced asymmetric solar wind-magnetosphere-ionosphere (SW-M-I) coupling between the northern and southern polar caps using ground-based and satellite-based data. Under prolonged conditions of strong earthward IMF on 5 March 2015, we find significant discrepancies between polar cap north (PCN) and polar cap south (PCS) magnetic indices with a negative bay-like change in the PCN and a positive bay-like change in the PCS. The difference between these indices (PCN-PCS) reaches a minimum of −1.63 mV/m, which is approximately three times higher in absolute value than the values for most of the time on this day (within ±0.5 mV/m). The high-latitude plasma convection also shows an asymmetric feature such that there exists an additional convection cell near the noon sector in the northern polar cap, but not in the southern polar cap. Meanwhile, negative bays in the north-south component of ground magnetic field perturbations (less than 50 nT) observed in the nightside auroral region of the Northern Hemisphere are accompanied with the brightening and widening of the nightside auroral oval in the Southern Hemisphere, implying a weak, but clear energy transfer to the nightside ionosphere of both hemispheres. After the hemispheric asymmetries in the polar caps disappear, a substorm onset takes place. All these observations indicate that IMF Bx-induced single lobe reconnection that occurred in the Northern Hemisphere plays an important role in hemispheric asymmetry in the energy transfer from the solar wind to the polar cap through the magnetosphere.

Moving beyond the T cell synapse for combination neoadjuvant immunotherapy in head and neck cancer

Abstract: Patients with HPV-unrelated head and neck squamous cell carcinoma (HPV-unrelated HNSCC) show only modest benefit from treatment with PD-1 inhibitors (PD-1i). Targeting transforming growth factor β (TGF-β) may make PD-1i more effective by inducing T cell responses. In this issue of the JCI, Redman et al. performed a clinical trial in 14 patients with HPV-unrelated HNSCC using bintrafusp alfa, a bifunctional fusion protein that blocks PD-L1 and TGF-β. Primary tumors displayed pathologic responses with 5 of 14 patients having at least a partial response. While no primary tumor or metastatic lymph node demonstrated a complete pathologic response, the findings suggest that concurrent neoadjuvant inhibition of PD-L1 and TGF-β may provide a rational strategy to improve pathologic response and clinical outcome in patients with HPV-unrelated HNSCC.

Rapid motion-free generation of interpulse delays for time-domain pump-probe spectroscopies with amplified fs pulses

Abstract: We present a dual-channel ultrafast amplifier delivering millijoule energy with electronically tunable delay of the output pulses from femtoseconds to milliseconds with femtosecond precision. Millijoule energies allow frequency-conversion enabling numerous applications in linear and nonlinear spectroscopy.

Computational Plasma Physics at (Almost) all Scales

Abstract: Computational plasma physics is a uniquely challenging field due to the extreme scales and disparate physical phenomena involved in the plasma universe. From electron cyclotron motion to resistive time-scales, from the plasma environment around black-holes to fusion machines, plasmas are ubiquitous in the visible universe. In this talk I will summarize the recent sophisticated numerical methods developed to simulate plasmas at (almost) all scales. These modern methods are carefully constructed to ensure preservation of underlying physical principles (like energy and positivity) and often arise from the considerations of the underlying Hamiltonian and Lagrangian structure of the equations. Based on higher-order finite-element or finite-volume schemes, these methods allow simulating a wide variety of problems, from laboratory to space plasmas. I will focus on modern discontinuous Galerkin (DG) schemes for kinetic equations, in which the 6D phase-space is directly discretized, in contrast to the standard particle-in-cell methods. I will show a variety of applications, from simulating planetary magnetospheres to turbulence in fusion machines. I will conclude with a prospectus for the future, which will likely involve the discovery of more efficient and robust methods that run on modern hardware architectures.

Reply on RC1

Abstract: This study investigates how the enhanced loading of microphysically and radiatively active aerosol particles impacts tropical sea breeze convection and whether these aerosol impacts are modulated by the multitudinous environments that support these cloud systems. To achieve these goals, we have performed two large numerical model ensembles, each comprised of 130 idealised simulations that represent different initial conditions typical of tropical sea breeze environments. The two ensembles are identical with the exception of the fact that one ensemble is initialised with relatively low aerosol loading or pristine conditions, while the other is initialised with higher aerosol loading or polluted conditions. Six atmospheric and four surface parameters are simultaneously perturbed for the 130 initial conditions. Analysis of the ten-dimensional parameter simulations was facilitated by the use of a statistical emulator and multivariate sensitivity techniques. Comparisons of the clean and polluted ensembles demonstrate that aerosol direct effects reduce the incoming shortwave radiation reaching the surface, as well as the outgoing longwave radiation, within the polluted ensemble. This results in weaker surface fluxes, a reduced ocean-land thermal gradient, and a weaker sea breeze circulation. Consequently, irrespective of the different initial environmental conditions, increasing aerosol concentration decreases the three ingredients necessary for moist convection: moisture, instability, and lift. As reduced surface fluxes and instability inhibit the convective boundary layer development, updraft velocities of the daytime cumulus convection developing ahead of the sea breeze front are robustly reduced in the polluted environments. Furthermore, the variance-based sensitivity analysis reveals that the soil saturation fraction is the most important environmental factor contributing to the updraft velocity variance of this daytime cumulus mode, but that it becomes a less important contributor with enhanced aerosol loading. It is also demonstrated that enhanced aerosol loading results in a weakening of the convection initiated along the sea breeze front. This suppression is particularly robust when the sea breeze-initiated convection is shallower, and hence restricted to warm rain processes. However, when the sea breeze-initiated convection is deep and includes mixed-phase processes, both the sign and magnitude of the convective updraft responses to increased aerosol loading are modulated by the environment. The less favourable convective environment arising from aerosol direct effects also restricts the development of sea breeze-initiated deep convection. While precipitation is ubiquitously suppressed with enhanced aerosol loading, the magnitude of this suppression remains a function of the initial environment. Altogether, our results highlight the importance of evaluating aerosol impacts on convection systems under the wide range of environments supporting such convective development.

From Practice to Posture

Abstract: Diversity, equity, inclusion, and belonging work has been an important element of organizational change in the last several years. However, there is much to critique as organizations struggle to see collective growth away from performative action and towards authentic internal change that is fully embodied from the top down. This chapter describes the importance and process of growth in educational leaders seeking to invest in the work of diversity, equity, inclusion, and belonging. The purpose of this chapter is to provide guidance to educational leaders and consultants who are seeking authentic ways to promote DEIB work and adult learning that fosters real results in DEIB. The chapter describes practices and ways of being, or a posture of authenticity that educational leaders should adopt if they want to see true organizational change within their professional community.

Reply on RC2

Abstract: Abstract. This study investigates how the enhanced loading of microphysically and radiatively active aerosol particles impacts tropical sea breeze convective systems and whether these impacts are modulated by the many environments that support these cloud systems. Comparisons of two 130-member pristine and polluted ensembles demonstrate that aerosol direct effects reduce the surface incoming shortwave radiation and the surface outgoing longwave radiation. Changes in the ensemble median values of the surface latent heat flux, the mixed layer depth, the mixed layer convective available potential energy, the maximum inland sea breeze extent, and the sea breeze frontal lift suggest that enhanced aerosol loading generally creates a less favorable environment for sea breeze convective systems. However, the sign and magnitude of these aerosol-induced changes are occasionally modulated by the surface, wind, and low-level thermodynamic conditions. As reduced surface fluxes and instability inhibit the convective boundary layer development, updraft velocities of the daytime cumulus convection developing ahead of the sea breeze front are robustly reduced in polluted environments across the environments tested. Statistical emulators and variance-based sensitivity analyses reveal that the soil saturation fraction is the most important environmental factor contributing to the updraft velocity variance of this daytime cumulus convection, but that it becomes a less important contributor with enhanced aerosol loading. It is also demonstrated that increased aerosol loading generally results in a weakening of the sea-breeze-initiated convection. This suppression is particularly robust when the sea-breeze-initiated convection is shallower and, hence, restricted to warm rain processes. While the less favorable convective environment arising from aerosol direct effects also restricts the development of sea-breeze-initiated deep convection in some cases, the response does appear to be environmentally modulated, with some cases producing stronger convective updrafts in more polluted environments. Sea breeze precipitation is ubiquitously suppressed with enhanced aerosol loading across all of the environments tested; however, the magnitude of this suppression remains a function of the initial environment. Altogether, our results highlight the importance of evaluating both direct and indirect aerosol effects on convective systems under the wide range of convective environments.

Conceptual design of DALS test facility cryogenic system

Abstract: Abstract Dalian advanced light source (DALS) is a new project proposed by Dalian Institute of Chemical Physics (DICP) aiming to produce high-quality electron beam with repetition rate up to 100 kHz and the project is subject to central government approval. The cryomodules and superconducting cavities need to be tested before assembled in the real accelerator so the test facility is necessary. The Accelerator module test facility (AMTF) project has been funded by Dalian local government and is currently under construction as the pre-research project for DALS, it consists of four testbenches, one Horizontal testbench (HTB) for cryomodule test, one Vertical testbench (VTB) for cavity test, one Cryogenic testbench (CTB) for cryogenic test and one Injector testbench (ITB) for beam test. A Test facility cryoplant (TFCP) with capacity of 370 W@2 K will be used for cooling testbenches. This paper presents the design and current progress of the TFCP system, which includes the refrigerators, helium compressors, process vacuum pump system (PVPS), gas storage system, recovery and purification system.

Is Europa Active and Suitable for Life? - How Europa Clipper and its Habitability Assessment Board (HAB) are working to synthesize observations to characterize Europa and its potential activity.

Abstract: &lt;p&gt;&lt;strong&gt;Introduction:&lt;/strong&gt; The habitability of Europa is a property within a system, with many interdependent physical and chemical parameters, among a number of processes, of which no single measurement or investigation can characterize. Therefore, investigating Europa as an integrated system must occur to understand the complete picture. To accomplish this, the Europa Clipper mission has three main mission objectives to assess Europa&amp;#8217;s habitability: (1) characterize the Ice Shell and Ocean: including their heterogeneity, properties, and the nature of surface&amp;#8211;ice&amp;#8211;ocean exchange; (2) characterize the Composition: understanding Europa&amp;#8217;s ocean through investigations of the composition and chemistry; (3) and characterize the Geology: including surface features and high-science-interest localities. Europa Clipper will also assess any current or recent activity by searching for evidence of thermal anomalies and plumes and will perform high resolution observations to provide reconnaissance for a future potential landed mission. Synthesizing the mission&amp;#8217;s science measurements in such a way as to constrain Europa&amp;#8217;s habitability is a complex task and is being guided by the Habitability Assessment Board (HAB).&lt;/p&gt;&lt;p&gt;The HAB is charged with providing a high-level, cross-instrument and cross-discipline, habitability-driven science perspective. All members of the Europa Clipper Science Team are considered members of the HAB and so contribute to addressing the overarching goal of the mission. Rotating members of the science team serve as leadership of the HAB and convene regular meetings to discuss and formulate recommendations to the project&amp;#8217;s science leadership. Particularly, HAB works to connect activities and measurements across the Europa Clipper Geology, Composition, and Interior Working Groups to investigate habitability and can recommend formation of focus groups of experts on the team to address scientific and technical problems related to habitability.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;System Science:&lt;/strong&gt; To achieve mission level 1 requirements and assess Europa&amp;#8217;s habitability, investigations will contribute observations towards science themes. Themes that support the Ice Shell and Ocean characterization include Full Depth Subsurface Exchange, Shallow Subsurface Structure, Ice Shell Properties, and Ocean Properties. For Composition characterization, themes that contribute include Global Composition Surface Mapping, Regional Composition, Atmospheric Composition, and Space Environment Composition. The Geology objective has contributions of Global Surface Mapping, Landform Geology, and Local Scale Surface Properties (which also contributes to reconnaissance). Current activity is supported by Remote Plume Search (and Characterization, if applicable), In-Situ Plume Search (and Characterization, if applicable), Surface Thermal Anomaly Search, and Surface Activity Evidence.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Current Activity:&lt;/strong&gt; Searches for and characterization of any recent activity would greatly contribute to assessing Europa&amp;#8217;s habitability. Europa Clipper plans observations for potential activity through remote observations including: the Europa-Ultraviolet Spectrograph (Europa-UVS) instrument through occultations, aurora, and UV scans; the Europa Imaging System (EIS) Narrow Angle Camera (NAC) through high resolution imaging; and the Europa Thermal Imaging System (E-THEMIS) through thermal infrared mapping. Additionally, in-situ measurements by the SUrface Dust Analyzer (SUDA) will also make observations of activity through detections of positive and negative ions and characterization of particle compositions and their locations of origin on the surface. Contributions by the other instruments will also inform on current/recent activity through remote and in-situ observations through magnetic, plasma, radar, and compositional measurements.&lt;/p&gt;&lt;p&gt;Remote observations to search for (and characterize if present) current activity at Europa by ground based, near-earth orbiting observatories, and other spacecraft could also occur, even while Europa Clipper is in transit to Jupiter. Recent observations by the Hubble Space Telescope (HST) have made putative detections of plume activity at Europa (Roth et al., 2014; Sparks et al., 2016) and future observations by the James Webb Space Telescope (JWST) and ground-based observatories may be able to confirm these findings. JWST can make measurements in the mid-infrared, for which the Galilean moons are relatively poorly characterized, enabling further constraints on composition and mechanisms driving the activity. Other observatories including the Very Large Telescope (VLT), the Atacama Large Millimeter/submillimeter Array (ALMA), and measurements by the Juno spacecraft and future JUICE mission could all contribute further to assessing Europa&amp;#8217;s potential activity and habitability. The Europa Clipper science team is currently working to informally coordinate efforts with the JUICE team to enhance our science as possible at Europa on a non-interference basis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt; Europa Clipper will assess the habitability of Europa as a system, guided by the HAB, through the synergy of multiple measurements and incorporation of remote observations by JWST and other remote observatories and spacecraft. Potential detections (and subsequent characterization) of any activity would greatly contribute to understanding Europa&amp;#8217;s habitability and potential to harbor life. Discovery awaits!&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Roth et al. (2014), Transient water vapor at Europa&amp;#8217;s south pole.&amp;#160;&lt;em&gt;Science&lt;/em&gt;,&amp;#160;&lt;em&gt;343&lt;/em&gt;(6167), 171-174.&lt;/p&gt;&lt;p&gt;Sparks et al. (2016), Probing for evidence of plumes on Europa with HST/STIS.&amp;#160;&lt;em&gt;The Astrophysical Journal&lt;/em&gt;,&amp;#160;&lt;em&gt;829&lt;/em&gt;(2), 121.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgments&lt;/strong&gt;: This work was supported by NASA through the Europa Clipper Project. Portions of this work were performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.&amp;#160;&lt;/p&gt;