Weak Turbulence and Quasilinear Diffusion for Relativistic Wave-Particle Interactions Via a Markov Approach

We derive weak turbulence and quasilinear models for relativistic charged particle dynamics in pitch-angle and energy space, due to interactions with electromagnetic waves propagating (anti-)parallel to a uniform background magnetic field. We use a Markovian approach that starts from the consideration of single particle motion in a prescribed electromagnetic field. This Markovian approach has a number of benefits, including: 1) the evident self-consistent relationship between a more general weak turbulence theory and the standard resonant diffusion quasilinear theory (as is commonly used in e.g. radiation belt and solar wind modeling); 2) the general nature of the Fokker-Planck equation that can be derived without any prior assumptions regarding its form; 3) the clear dependence of the form of the Fokker-Planck equation and the transport coefficients on given specific timescales. The quasilinear diffusion coefficients that we derive are not new in and of themselves, but this concise derivation and discussion of the weak turbulence and quasilinear theories using the Markovian framework is physically very instructive. The results presented herein form fundamental groundwork for future studies that consider phenomena for which some of the assumptions made in this manuscript may be relaxed.

On the Origins of the Oceanic Ultraviolet Catastrophe

We provide a first-principles analysis of the energy fluxes in the oceanic internal wavefield. The resulting formula is remarkably similar to the renowned phenomenological formula for the turbulent dissipation rate in the ocean which is known as the Finescale Parameterization. The prediction is based on the wave turbulence theory of internal gravity waves and on a new methodology devised for the computation of the associated energy fluxes. In the standard spectral representation of the wave energy density, in the two-dimensional vertical wavenumber – frequency (m – w) domain, the energy fluxes associated with the steady state are found to be directed downscale in both coordinates, closely matching the Finescale-Parameterization formula in functional form and in magnitude. These energy transfers are composed of a ‘local’ and a ‘scale-separated’ contributions; while the former is quantified numerically, the latter is dominated by the Induced Diffusion process and is amenable to analytical treatment. Contrary to previous results indicating an inverse energy cascade from high frequency to low, at odds with observations, our analysis of all non-zero coefficients of the diffusion tensor predicts a direct energy cascade. Moreover, by the same analysis fundamental spectra that had been deemed ‘no-flux’ solutions are reinstated to the status of ‘constant-downscale-flux’ solutions. This is consequential for an understanding of energy fluxes, sources and sinks that fits in the observational paradigm of the Finescale Parameterization, solving at once two long-standing paradoxes that had earned the name of ‘Oceanic Ultraviolet Catastrophe’.

The Spatial Structure of Passively Simulated Atmospheric Boundary Layer Turbulence

Three types of turbulence fields were investigated using a research method combining wind tunnel tests and theoretical analysis to further explore the spatial structure of atmospheric boundary layer turbulence, which was passively simulated by a wind tunnel. The fundamental theory of turbulence is introduced, and some traditional theoretical coherence models based on isotropic turbulence theory are derived. The difference between the theoretical results and the passive simulation of atmospheric boundary layer turbulence was compared and discussed. The analysis results show that the passively simulated atmospheric turbulence basically conformed to the homogeneous isotropic turbulence assumption on the horizontal plane, but the interference of the nonisotropic turbulence components cannot be ignored either. Finally, some improvements were made to the traditional coherence function model based on the experimental results to apply the passively simulated atmospheric boundary layer turbulence.

Caregiving spouses’ experiences of relational uncertainty and partner influence in the prolonged relational transition of Alzheimer’s disease and related dementias

Alzheimer’s disease and related dementias cause gradual cognitive and communicative decline over a period of several years creating a prolonged transitional period in the lives of people with the disease and their spouse. Relational turbulence theory served as a lens to examine 18 in-depth interviews with caregiving spouses regarding their experiences of relational uncertainty, and interference and facilitation from their partner throughout this prolonged relational transition. Counterintuitively, the experience of relational uncertainty was greatly influenced by the certainties of relational change and termination (death) that shifted the temporal focus of uncertainty to the future. Communicative symptoms and aggressive behavior were a main source of interference. Despite the impairment of the disease, caregiving spouses recognized their partners’ expressions of gratitude, moments of recognition, and simple expressions of love as facilitation.

Caregivers' Loss of the Dyadic Experience After Their Care Partner's Death

One emerging dyadic concept is the experience of family caregivers when their care partner dies and their dyadic relationship comes to an end. This study qualitatively examined and characterized the loss of the dyadic experience for the caregiver after the death of their care partner. Data was accrued as part of a randomized clinical trial in 29 older hospice caregivers. Iterative thematic analysis focused on dyadic processes before, during and post death. Using two relational parameters from Relational Turbulence Theory resulted in a preliminary characterization of a new concept - dyadic dissolution as a cognitive and affective process whereby a remaining member of a dyad experiences relational uncertainty and partner interference while adapting (or not) to the death of their care partner. Findings suggest that asking several open-ended questions about the dyadic relationship will enable assessment for any continuing impact of relational uncertainty and partner interference on bereaved caregivers.

Local similarity theory of convective turbulent layer using ‘spectral’ Prandtl mixing length and second moment of vertical velocity

Approximations of the turbulent moments of the atmospheric convective boundary layer are constructed based on a variant of the local similarity theory. As the basic parameters of this theory, the second moment of vertical velocity and the ‘spectral’ Prandtl mixing length are used. This specific choice of the basic parameters allows us to consider the coefficient of turbulent transfer and the dissipation of kinetic energy of the Prandtl turbulence theory as the forms of the local similarity. Therefore, the obtained approximations of the turbulent moments should be considered as natural complementation to the semi-empirical turbulence theory. Moreover, within the atmospheric surface layer, the approximations of the new local similarity theory are identical to the relations of the Monin-Obukhov similarity theory (MOST). Therefore, the proposed approximations should be considered as a direct generalization of the MOST under free convection conditions. The new approximations are compared with the relations of the known local similarity theories. The advantages and limitations of the new theory are discussed. The comparison of the approximations of the new local similarity theory with the field and laboratory experimental data indicates the high effectiveness of the proposed approach.

Unifying turbulent dynamics framework distinguishes different brain states

Recently, significant advances have been made by identifying the levels of synchronicity of the underlying dynamics of a given brain state. This research has demonstrated that unconscious dynamics tend to be more synchronous than those found in conscious states, which are more asynchronous. Here we go beyond this dichotomy to demonstrate that the different brain states are always underpinned by spatiotemporal chaos but with dissociable turbulent dynamics. We investigated human neuroimaging data from different brain states (resting state, meditation, deep sleep, and disorders of consciousness after coma) and were able to distinguish between them using complementary model-free and model-based measures of turbulent information transmission. Our model-free approach used recent advances describing a measure of information cascade across spatial scales using tools from turbulence theory. Complementarily, our model-based approach used exhaustive in silico perturbations of whole-brain models fitted to the empirical neuroimaging data, which allowed us to study the information encoding capabilities of the brain states. Overall, the current framework demonstrates that different levels of turbulent dynamics are fundamental for describing and differentiating between brain states.

The role of identity uncertainty in predicting relational turbulence and perceived partner communication for women coping with infertility

Infertility can change the way people see themselves and their relational roles. This study examined how changes to identity following reproductive hardship are associated with identity uncertainty and relationship outcomes. Drawing on relational turbulence theory, we position identity uncertainty as an antecedent condition for relational uncertainty and interdependence processes in the context of infertility and examine these relationship mechanisms as predictors of relational turbulence and perceptions of partner communication during this relationship transition. We surveyed 152 women who have been unsuccessful at conceiving for at least 12 months about their identity and perceptions of their relationship. Data were analyzed using structural equation modeling. Consistent with hypotheses, identity change was positively associated with identity uncertainty, which, in turn, predicted increased relational uncertainty. Relational turbulence was positively predicted by relational uncertainty, but not partner interference or facilitation. Perceptions of a partner’s communication were predicted by relational turbulence and partner facilitation. The theoretical and practical implications of the findings are discussed.