Abstract The interactions between energetic ions (EIs) and kinetic ballooning modes (KBMs) are inevitable in fusion reactors characterized by high-$\beta$ plasmas with a large population of alpha particles ($\beta_h\sim\beta_{e,i}$, where $\beta_{h,e,i}=2\mu_0p_{h,e,i}/B_0^2$). In this work, the EI effects on KBM stability are investigated using first-principle gyrokinetic simulations, which demonstrate the roles of MHD ballooning-interchange drive, wave-particle resonance and orbital effects in several parameter regimes of practical interest. In particular, it is found that EI-KBM interactions are mostly determined by three dimensionless parameters: EI-thermal electron temperature ratio $T_h/T_e$, KBM perpendicular wave vector normalized by EI orbit width $k_\theta\rho_d$ and EI pressure ratio $\beta_h$, which associate with resonance condition, finite orbit width (FOW) screening and EI drive strength for Alfvénic modes. For typical orderings of $T_h/T_e\gg1$ and $\beta_h\sim\beta_{e,i}$, the $k_\theta\rho_d$ becomes crucial for relevant physics processes: (i) In short wavelength regime of $k_\theta\rho_d\gg1$, EI response to KBM electromagnetic fluctuations is greatly reduced due to strong FOW screening, which leads to a weakly stabilizing effect on KBM via thermal ion dilution, despite the large $\beta_h$. (ii) In long wavelength regime of $k_\theta\rho_d\ll1$, passing EIs can non-perturbatively destabilize KBM through transit motion resonance, attributing to the fact that large poloidal and toroidal frequencies mostly cancel each other and satisfy $\omega=n\omega_\phi-p\omega_\theta$ locally around $q=p/n$ rational surfaces ($p$ is an integer), while trapped EI net response is near zero due to the mismatch of resonance condition. For minor ion species characterized by $T_h/T_e\gtrsim$ 1 such as helium ash, the FOW screening is modest with $k_\theta\rho_d\sim1$ and the drive strength is perturbative with $\beta_h\ll\beta_{e,i}$, which drive KBM through MHD ballooning-interchange and wave-particle resonance similar to thermal ions. These findings are helpful for understanding alpha particle and helium ash effects on KBM stability and plasma confinements in future fusion reactors.

Abstract The High Arctic Large Igneous Province (HALIP) formed in the circum‐Arctic during the Cretaceous. The timing and duration of emplacement of these mafic magmas are important for understanding the climatic and environmental effects, yet many uncertainties remain. The dating methods used vary greatly between different regions. For example, the mafic intrusions in Svalbard have mainly been dated using the 40 K/ 40 Ar method, which is more sensitive to overprinting at lower temperatures. This is problematic especially in the Arctic, where the Eocene Eurekan orogeny has impacted the intrusions post‐emplacement. Meanwhile, in the Canadian Arctic, 206 Pb/ 238 U dating on zirconium minerals has been the most common method employed, which requires much higher temperatures to be reset. We present a new compilation of ages for HALIP igneous and volcanic rocks in the circum‐Arctic, derived from a thorough review and reassessment of previously reported data. This compilation applies rigorous, method‐specific criteria to evaluate the reliability of existing HALIP age determinations, ensuring traceability and applicability for future data sets. By establishing a robust framework for assessing age data, this approach enhances the reliability of geological interpretations of HALIP magmatism, and highlights, for example, the spatial migration of peak magmatic activity through time in the High Arctic. To improve our understanding of the temporal evolution of the HALIP, we also present a new 206 Pb/ 238 U baddeleyite isotopic dilution thermal ionization mass spectrometry age from Svalbard. The new weighted mean 206 Pb/ 238 U age from Svalbard, 123.3 ± 1.6 Ma, is based on six samples belonging to one large sill. This age is in perfect agreement with existing published 206 Pb/ 238 U and 40 Ar/ 39 Ar ages, and suggests magma emplacement on Svalbard between 124.7 ± 0.3 and 120.2 ± 1.9 Ma ago.

Abstract Turbulence causes anomalous transport of plasma and thus limits achieving high temperature and density of magnetically confined fusion plasmas. Recently, fast-ion-driven Alfvénic instabilities were found to influence plasma thermal confinement by regulating turbulence. However, both favourable and unfavourable effects coming from various mechanisms have been reported from experiments and simulations to date. Here, we report a key parameter (ratio between growth rate of Alfvénic instability and that of microturbulence) which can characterise changes in heat transport of thermal ions due to nonlinear interaction between the fast-ion-driven Alfvénic instabilities and microturbulence in tokamak plasmas. The transition from transport enhancement to reduction occurs at a particular value of the parameter as it gets higher, and is reminiscent of the bifurcation responsible for transport-barrier formation. This simple characterisation successfully covers the trend of experimental results, and can provide a useful guideline for realising high performance confinement of burning plasmas in which fast ions are abundant.

Abstract Hot ion mode has been achieved on HL-2A tokamak with a low electron density and a moderate neutral beam injection power. It is characterized by a high ratio of ion temperature (T_i) and electron temperature (T_e). The T_i/T_e is higher than 3 and ion temperature reaches to 3.5keV in the experiments with heating power no more than 1.3MW. Strong internal transport barrier (ITB), fishbone modes, kinetic ballooning modes (KBM) and ion temperature gradient (ITG) modes are also observed in the hot ion plasma. Power balance analysis given by TRANSP code suggests that electron heating is dominant but thermal ion heat diffusivity is lower than the neoclassical diffusivity in ITB region. Further analysis based on GENE code shows the ITG modes induced heat transport is dominant in experiment, but KBM induced transport will play a more critical role when the electron beta reaches to 0.48\%. More interesting, the heat flux shows a great drop when the fast ions are taken into account. Those results may indicate that the fast ions have a stabilization effect on plasma turbulence, then reduce the thermal ion transport and finally contribute to achievement of high ion temperature and formation of hot ion mode.

We have investigated the rate of ionization of traps using the proper adiabatic approximation. This rate is usually described by an Arrhenius-type equation in the experimental determination of trap depths from thermoluminescence measurements,R = νe-E/kT where R is the rate of ionization, E is the trap depth, and ν is the frequency factor. Although Eq. 1 has the form of an Arrhenius equation, in the exponent is the trap depth, not the activation barrier, Eb , as in a typical Arrhenius equation. (See Figure 1.)In a typical analysis of glow curves, ν is assumed to be a constant, although a weak temperature dependence is generally indicated by various authors. We have formulated this trap ionization problem using the proper adiabatic approximation for a single configurational coordinate system. In our formulation the nonadiabaticity operator drives the system from the ground state to the excited state nonradiatively. Using a first-order perturbation theory we have obtained the transition rate using the Fermi golden rule. We show that E in the exponent is indeed the trap depth, and that has a weak temperature dependence. We investigated the effect of this temperature dependence on calculating the trap depth from the glow curves. This will be discussed in detail in the presentation. Fig. 1: Adiabatic potentials for the electron in the ground state of the trap and in the excited state following ionization for a single configurational coordinate system. Figure 1

Self-assembled monolayers (SAMs) can be terminated with various functional groups, which are often acido-basic groups (acid, amine, sulfonate etc...) bearing either a positive or negative net charge. The degree of ionization of the surface controls potential electrostatic interaction with charged species in solution. Nondestructive and simple ways of characterizing the surface charge of a SAM, in solution, is thus important. We propose an electro-analytical study of surface ionization based on the analysis of the voltammetric response of adsorbed redox species. Charged iron complexes are electrostatically adsorbed onto an ionized SAM and the width of the voltammetric peaks of the adsorbed redox couple is then analyzed with an electrostatic model accounting for potential drop within the SAM1 as well as electrostatic interactions between adsorbates and ionized terminal groups. We will present two mirror situations (positive redox couple onto a negative SAM and vice versa) to show the versatility of our approach. 1 Smith, C. P.; White, H. S. Theory of the Interfacial Potential Distribution and Reversible Voltammetric Response of Electrodes Coated with Electroactive Molecular Films. Anal. Chem. 1992, 64, 2398– 2405, DOI: 10.1021/ac00044a017

The results of the mass spectrometric studies of heterogeneous transformations of molecules of psychotropic drugs-piperidine and piperazine derivatives of butyrophenone haloperidol, trifluperidol, droperidol, and azaperone during adsorption on a hot surface of tungsten oxide-have been presented. The relationship between the channels of heterogeneous reactions and the nature of the adsorption centers in the molecules has been established. Ion current lines characteristic of the products of heterogeneous reactions of dehydrogenation, dissociation, and dehydrolysis of molecules with the elimination of up to two water molecules formed during aromatization of amine rings and hydrogen rearrangement with the participation of oxygen of the carbonyl group have been found in the mass spectra. A shift in the maximum yield of heterogeneous reactions towards low emitter-converter temperatures with an increase in the degree of dehydrogenation and dehydrolysis of radicals in the adsorbed layer has been found. At the same time, estimates have shown that within the emitter temperature range from 850 K to 1200 K, the lifetime of radicals in the adsorption layer is reduced from fractions of a second to tens of nanoseconds. At relatively high emitter temperatures (from 800 K), current lines of monomolecular decays of metastable parent ions have been detected. When using the surface of tungsten oxide as a positive ion converter, a high efficiency (up to 98%) of surface ionization of desorbed radicals has been established, making it possible to trace the complete picture of the heterogeneous reactions occurring in the adsorbed layer.

Abstract Low-temperature plasma-catalyzed ammonia synthesis is an environmentally friendly process well-suited for distributed energy systems. Among these methods, nanosecond pulsed discharge plasma has attracted significant attention due to its ability to rapidly generate large numbers of active particles that actively participate in chemical reactions. However, prior studies were constrained by experimental limitations: key reactive species were difficult to measure, their behavior during the discharge process was poorly understood. Besides, zero-dimensional kinetic models overlooked the spatial distributions of species, electron energies, and electric fields. In this study, the spatiotemporal evolution of key reactive species in a plasma-assisted ammonia synthesis system is investigated. A two-dimensional fluid model is developed for ammonia synthesis under nanosecond pulsed voltage. A coaxial dielectric barrier discharge (DBD) reactor with packed catalysts is employed to study the behavior of key species under varying peak voltages (vp), pulse rise times (tr), and catalyst dielectric constants (ε_r). The results indicate that plasma propagation inside the reactor occurs via surface ionization waves and filamentary micro-discharges. Under vp = −10 kV and ε_r = 9, the average densities of electrons, N2(v1), H2(v1), N, and H initially increased and then decreased as the pulse rise time increased from 10 ns to 40 ns, peaking at 20 ns. At tr = 10 ns and ε_r = 9, the average densities of all species increased with peak voltage. At tr = 10 ns and vp = −10 kV, the average densities of electrons, N, and H peaked at ε_r = 15, initially increasing and then decreasing as the dielectric constant varied from 9 to 25. In contrast, the average densities of N2(v1) and H2(v1) increased monotonically with the dielectric constant. The model offers a theoretical basis for improving the reaction rate and efficiency of ammonia synthesis in low-temperature plasma systems.

Constraints on the time scales of magmatic-hydrothermal processes are key factors in understanding the formation of mineral resources of economic importance that are associated with silicic magmatic systems, including porphyry Cu-Mo-Au systems, Sn-W greisens, and pegmatites. Zircon petrochronology is a widely used tool for determining crystallization ages and temperatures of magmatic systems. In this study, we used the Proterozoic A-type Pikes Peak batholith as a case study to discuss the time scales and chemistry of giant silicic systems, and their relationship with magmatic-hydrothermal mineralized zones. Such mineralizations occur as Nb-Y-F-pegmatites and as mineralized zones in the Redskin granite, a Nb-rich subunit of the Pikes Peak batholith, Colorado. We used zircon petrochronology, feldspar chemistry, and thermodynamic modeling coupled with trace-element modeling via Rayleigh fractionation to understand how the Pikes Peak melt evolved and generated the mineralized zones in the pegmatites and Redskin granite. Our results show that zircon from the main granite is typically magmatic, characterized by bright cathodoluminescence (CL), oscillatory zoning, and low U contents. Pegmatitic zircon grains, in contrast, show high degrees of metamictization, with dark CL and high U contents, indicating crystallization from a highly differentiated magmatic hydrous fluid. Zircon grains from the Redskin granites show bimodal compositions with both low- and high-U zircon grains, marking a transition from magmatic to hydrothermal crystallization. Through isotope dilution−thermal ionization mass spectrometry (ID-TIMS) dating of the Pikes Peak main granite and the late-stage Redskin granite, we obtained high-precision dates that allowed us to constrain the period from the beginning of the magmatic activity in the Pikes Peak batholith to the crystallization of late exsolved fluid phases contributing to pegmatite formation, spanning a temporal interval of at least 15 m.y. for the full lifetime of the system. Although extensive, the observed 15 m.y. duration for this large-sized batholith (>3000 km2) is comparable to other long-lived magmatic systems of similar size.

The interpretation of maximum depositional age (MDA) from U-Pb detrital zircon data acquired via laser ablation−inductively coupled plasma−mass spectrometry (LA-ICP-MS) or secondary ion mass spectrometry (SIMS) is now routine; however, to date only a few studies have presented tests of such MDAs by subsequently analyzing a subset of the same detrital zircon grains with the more accurate and precise chemical abrasion−isotope dilution−thermal ionization mass spectrometry (CA-ID-TIMS) method. We first generated LA-ICP-MS dates and MDAs from three turbidite sandstone samples of the Late Jurassic Mariposa Formation (Sierra Nevada foothills, California) containing large proportions of young detrital zircon grains (at the time of sediment deposition). We then removed 4−5 of the apparent youngest grains from the epoxy mount and analyzed them with CA-ID-TIMS. Despite a lack of low Th/U or high U (ppm) characteristics that might indicate U-Pb system disturbance, all LA-ICP-MS dates are younger than corresponding CA-ID-TIMS dates, on the same grain, by up to 11.8 m.y. when considered as point estimates. Only two out of 13 paired analyses overlap within error at 95% confidence. We interpret MDAs from our CA-ID-TIMS dates to be the youngest CA-ID-TIMS dates (YTDs). LA-ICP-MS MDAs based on fewer dates from the young tail of the youngest date distribution perform the worst (i.e., furthest from CA-ID-TIMS MDAs), whereas LA-ICP-MS MDA methods that incorporate more dates from the youngest date distribution perform better; the best performing method in all cases is the maximum likelihood algorithm−minimum. The performance of tested LA-ICP-MS MDA methods is improved by removing statistical outlier dates and by removing visually young “outlier” dates that drift away from the primary distribution of young dates. Our paired LA-ICP-MS/CA-ID-TIMS MDA workflow shows that the accuracy of MDA can be significantly improved by conducting CA-ID-TIMS on as few as four grains from a sample. The combination of our new CA-ID-TIMS MDAs with published CA-ID-TIMS analyses and petrochronology on the nearby Guadalupe igneous complex provides sub-million-year resolution of contemporaneous igneous and sedimentary systems during deformation and clarifies the timing of regional deformation that defines the local “Nevadan orogeny.” Rocks in the upper plate of the Bear Mountains fault zone have a CA-ID-TIMS YTD MDA of 151.71 ± 0.23 Ma, and rocks of the lower plate have a CA-ID-TIMS YTD MDA of 149.92 ± 0.11 Ma. These new MDAs, in conjunction with the observation of fabric-bearing Mariposa Formation xenoliths in the ca. 149.65 ± 0.10 Ma Guadalupe igneous complex, suggest that rocks in the upper plate of the Bear Mountains fault zone represent a slightly older (∼2 m.y.) section of Mariposa Formation that was deformed and intruded prior to being juxtaposed against, and further deformed with, a slightly younger lower-plate section of Mariposa Formation in actively deforming, fault-bounded basins. Our observations are not consistent with traditional models that require that sedimentation of the Mariposa Formation ended by ca. 155 Ma. Instead, we interpret our data to be consistent with other evidence for a continuum of deformation in Late Jurassic to Early Cretaceous time and document that the regional “slatey cleavage” observed in the greater Mariposa Formation and used to define the “Nevadan orogeny” in our study area is largely younger than 149.92 ± 0.11 Ma.

Abstract Nanosecond surface dielectric barrier discharge (ns-SDBD) actuators have broad applications in flow control, where the discharge characteristics are significantly influenced by the pulse repetition frequency (PRF) through its modulation of surface ionization wave (SIW) dynamics. This study investigates the effects of PRFs and nanosecond-pulse number on energy accumulation mechanisms, discharge mode transitions, and SIW propagation in SDBDs. Experimental results show distinct discharge characteristics in the case of two dielectric barriers, epoxy glass cloth (FR-4) and polytetrafluoroethylene (PTFE), respectively. In the case of FR-4, the single-pulse energy initially increases with higher PRFs and pulse numbers, but subsequently decreases after reaching its peak. In the case of PTFE, the results demonstrate pronounced energy accumulation, with energy continuously increasing under the same conditions. Furthermore, SDBD actuators with PTFE require significantly higher PRF thresholds and greater pulse quantities to induce transitions in discharge mode compared to those with FR-4. At elevated PRFs, both materials exhibit accelerated propagation of SIW and streamers as the PRF and pulse number increase. However, while SIW propagation tends to saturate at high PRFs, streamer velocity shows a slightly saturated trend under similar conditions. These findings provide critical insights for optimizing ns-SDBD performance through proper material selection and PRF control in practical applications.

An analytic study is conducted on the gyro-average operation of magnetized ions in the asymptotic limit of the high-wavenumber electromagnetic fluctuations. This method is suitable for evaluating the gyro-averaged potential experienced by energetic particles or thermal ions in magnetic fusion plasmas when the fluctuation scale length is significantly shorter than the ion Larmor radius. The methodology of two-dimensional fractional calculus is shown to be essential for the computation of the gyro-average operator in this limit. Making use of the asymptotic expression for the operator, we obtain a new formula expressed by the Riesz potential of order 3/2. We also derive the double gyro-average operator in terms of spatial differential operation. Finally, the same problem is considered from a statistical viewpoint. Under the assumption of the von Mises distribution of fluctuations due to the periodicity of the fluctuation along the orbit, we obtain an expectation value which should be identical to the direct calculation of the gyro-averaged potential represented by the integral transform.

Evaluation of thermal desorption–electrospray ionization mass spectrometry for characterization of Mycobacterium tuberculosis: Comparison with MIRU-VNTR and whole-genome sequencing

Abstract In scenarios where a sustained energetic particle source strongly drives toroidal Alfvén eigenmodes (TAE), and phase-space transport is insufficient to saturate TAE, this novel theory of TAE-zonal mode (ZM)-turbulence—self-regulated by cross-scale interactions (including collisionless ZF damping) – merits consideration. Zonal modes are driven by Reynolds and Maxwell stresses, without the onset of modulational instability. TAE evolution in the presence of ZMs conserves energy and closes the system feedback loop. The saturated zonal shears can be sufficient to suppress ambient drift-ion temperature gradient (ITG) turbulence, achieving an enhanced core confinement regime. The saturated state is regulated by linear and turbulent zonal flow drag. This regulation leads to bursty TAE spectral oscillations, which overshoot while approaching saturation. Heating by both collisional and collisionless ZM damping deposits alpha particle energy into the thermal plasma, achieving effective alpha channeling. This theory offers a mechanism for EP-induced transport barrier formation, and predicts a novel thermal ion heating mechanism.

Hydrogel adhesion is a complex process that involves chain dynamics, thermodynamics, chemistry, and topology. Using fluorescent confocal microscopy in combination with fluorescent differential dynamic microscopy (fDDM), we have determined surface deformation and dynamics of cross-linked hyaluronic acid (HA) gels, equilibrated against 1-1000 mM NaCl solutions, at positively and negatively ionized surfaces. Due to the negative ionization of HA, the gels are repelled from negatively ionized glass surfaces creating a fluid separation layer and repulsion remains unaffected by salt concentration. At these interfaces, the gel network motion is slowed, as determined with fDDM in 167 mM ionic strength. To create positively ionized surfaces, poly-L-lysine is deposited on the glass surface. At higher salt concentrations, surface ionization has little effect, while in lower salt concentrations, the softer gels are compressed 4-6 times by the surface forces. In lower salt concentrations, the surface interactions are less screened and the gels are softer, leading to greater deformation. These results reveal that gel deformation and interfacial dynamics are governed by a delicate interplay between gel modulus, surface ionization, and ionic strength, underscoring the need for new theoretical models to predict soft gel behavior at interfaces and enabling the rational design of gel-based adhesives, coatings, and biointerfaces.

Silicon clathrates (SiCL) are a class of cage-structured materials with tuneable optoelectronic properties, offering significant potential for photovoltaic applications. Among them, type II SiCL (NaxSi136) are particularly attractive due to their unique ability to reversibly accommodate guest atoms without compromising the crystal structure. Traditional synthesis methods, such as synthesis under extreme pressure or fabrication under glove boxes, although essential for probing the intrinsic properties of clathrates under well-controlled conditions, are not well-suited for scaling up and are often energy-intensive and require specialized equipment. To overcome these limitations, a scalable, glovebox-free synthesis method based on two thermal decomposition steps was developed to produce silicon clathrate films. Post-synthesis treatment, including thermal pressing and reactive ion etching, was employed to enhance the electrical properties of the material. Phase formation and crystallinity are confirmed by X-ray diffraction and Raman spectroscopy; morphology is assessed by scanning electron microscopy (SEM); and optoelectronic properties are evaluated by photoluminescence. This approach provides a reproducible and scalable route to fabricate type II silicon clathrate films, with promising potential for integration into optoelectronic devices.

Abstract The Negative Triangularity (NT) plasma edge is studied with full orbit simulations and compared with similar simulations using a Positive Triangularity (PT) edge geometry. It is found that the thermal edge ions in NT are less well confined than in PT. The edge ion losses in NT set-up an electric field inside the plasma in the loss region. This electric field leads to counter-current edge plasma flows and are consistent with observations in NT plasmas. It could also explain the good edge confinement in NT discharges via the E × B flow shear turbulence suppression mechanism.

Abstract. Zircon petrochronology is widely used to quantify the age and duration of magma emplacement and differentiation. However, in highly differentiated magmas, such as those forming rare-metal granites, zircon may form at the magmatic–hydrothermal transition, and its primary crystallisation history, together with its secondary hydrothermal overprint, needs to be resolved and clarified. To resolve zircon formation in such evolved and mineralised granitic systems, we investigated heterogeneous zircons from the Beauvoir rare-metal granite (Massif Central, France). Most of the Beauvoir zircons are characterised by the presence of two distinct domains, designated as Zone 1 and Zone 2. Zone 1 occurs as rounded, Si- and Zr-rich domains, which are embedded in the interconnected Si- and Zr-poor Zone 2 domains that are also extremely P-, U-, F-, Ca-, Fe- and Mn-rich. Both of these zones are strongly damaged (metamict) by radioactive decay, mainly from their high U concentrations. Textures and chemical composition strongly suggest that Zone 1 corresponds to magmatic zircon that has been partly replaced by the Zone 2 material during the magmatic–hydrothermal transition. The crystallisation of Zone 1 zircon is preceded by the crystallisation of U-rich cores (∼6 wt % UO2) containing UO2 (uraninite) micro-inclusions, which are then surrounded by a Zone 1 homogeneous rim. These uraninite micro-inclusions resulted from the uranium migration in the metamict and amorphous precursor zircon. U-Pb dating of single zircon grains using chemical abrasion, isotope dilution thermal ionisation mass spectrometry (CA-ID-TIMS) techniques yielded a well-defined discordia line with an upper intercept at 312±2.9 (7.2) Ma (2σ) and a near-zero-age lower intercept. The discordancy reflects the continuous loss of radiogenic lead from a heavily damaged and aperiodic zircon lattice. On the other hand, ID-TIMS data from magmatic apatite of the Beauvoir granite yielded an age of 313.4±0.2 (1.3) Ma (2σ), so far, the most accurate and precise crystallisation age of the Beauvoir granite. Thus, we emphasise that although the study of zircon from highly differentiated systems provides strong insights into the magmatic–hydrothermal transition of these objects, their metamict nature prevents their use to precisely and accurately date the emplacement of rare-metal granite.

Abstract The physical processes behind astrophysical collisionless shocks, such as thermal relaxation and ionization after shock passage, remain poorly understood. To investigate these processes, we analyze the northeastern region of the Cygnus Loop with XMM-Newton. The electron temperature is found to increase toward the interior of the remnant ranging from 0.15 to 0.19 keV energy range within a spatial scale of 6′ (or 1.27 pc at a distance of 725 pc) from the shock front. This can be explained well by a modified Sedov solution with radiative cooling. We also show that the ionization timescales determined from our spectroscopy are significantly larger than those estimated based on the electron density of the surrounding materials and the shock velocity. This excess can be qualitatively explained by a mixing of inner multiple plasma components with different ionization states due to turbulence.

The tempting interpretation of ion cyclotron emission in terms of compressional Alfvén eigenmodes involving energetic ions is inconsistent with recent TCV experimental observations in some important aspects, such as (i) the perturbed poloidal field is exceeding the parallel perturbed magnetic field significantly, and (ii) the modes are near cyclotron harmonic and exhibit Alfvèn scaling of their frequency. We show that these characteristics can be explained by considering finite Larmor radius effects of thermal ions in shear Alfvén waves that allow such waves to exist well above the ion cyclotron frequency in the form of wave-packets bouncing within the plasma volume.