Similar Discharges Research Articles

ELM-free H-mode phase and decoupling of peeling-ballooning stability boundary in MAST Upgrade tokamak

Abstract The linear MHD peeling-ballooning stability analysis on the ELM-free phase of MAST Upgrade H-mode plasma is presented. In contrast to other similar discharges, #47018 is found to have significantly higher and wider pedestal during an ELM-free H-mode phase that lasts for approximately 80ms, which is made possible by the reduced core MHD mode activity on q=2 surface. During this period, there is sustained decoupling of peeling and ballooning branches of the stability boundary on J-α space, opening an access channel to the second stability regime with higher peaks in pedestal current density J N,ped and pressure gradient (α). Such decoupling of the stability boundary is not previously observed in MAST Upgrade H-modes, and if such condition can be readily reproduced, it opens a wide range of opportunity for MAST-U to explore low-collisionality peeling-limited pedestal regimes, as well as advanced scenarios such as quiescent H-modes that are relevant to future reactors, such as STEP and ITER.

Origin of the up/down poloidal asymmetric dependence of ELM control in ITER-like RMP configuration in KSTAR

Recent edge-localized modes (ELM) control experiments via resonant magnetic perturbation (RMP) in KSTAR have shown a strong up/down poloidal asymmetric coupling dependence. Specifically, in lower single null (LSN) plasmas at q95 ≳ 5, the lower two-row (middle/bottom) RMPs among ITER-like three-row (top/middle/bottom) in-vessel control coils (IVCC) in KSTAR were more effective in suppressing ELM-crashes than the upper two-row (top/middle) RMPs. In contrast, at q 95 ∼ 4, the upper two-row RMPs turned out to be more effective than the lower counterpart. Since the ITER baseline scenario is planned to operate at q 95 ∼ 3, the understanding of the origin of such up/down poloidal asymmetric coupling dependence, as well as the prediction about ITER-relevant conditions at a lower q 95, would be quite important and potentially impactful to the RMP ELM control in ITER. A linear, resistive, single-fluid MHD code MARS-F has been utilized to address and model the up/down poloidal asymmetric RMP coupling dependence. Specifically, based on two contrasting exemplary discharges with up/down poloidal (i) asymmetric at q 95 ∼ 4 and (ii) symmetric behavior at q 95 ∼ 5, among tens of otherwise similar discharges, a systematic MARS-F modeling has been thoroughly conducted. As a result, the plasma response investigation suggests that the X-point displacement (ξ X), rather than any other figures of merit, would be a directly relevant metric for the up/down poloidal asymmetric coupling in RMP-driven, ELM-crash suppression in KSTAR. Based on a sensitivity study of the edge safety factor in MARS-F modeling, the ξ X variation follows the same quantitative trend as observed in experiments. However, no or little plasma pressure dependence has been found, though ξ X increases with plasma pressure. At the ITER-relevant low q 95 ∼ 3 in a scaled KSTAR equilibrium, such modeling predicts the upper two-row RMPs would be more favorable in suppressing the ELM-crashes than the lower counterpart.

Scale-invariant breathing oscillations and transition of the electron energization mechanism in magnetized discharges

Scale-invariant breathing oscillations are observed in similar magnetized discharges at different spatiotemporal scales via fully kinetic particle-in-cell simulations. With an increase in the similarity invariant B/p, i.e., the ratio of magnetic field to pressure, breathing oscillations are triggered, leading to an appreciable time-averaged potential fall outside the sheath. With the onset and development of breathing oscillations, the electron energization mechanism shifts from sheath energization to direct Ohmic heating in the ionization region due to the change in the potential fall inside and outside the cathode sheath. Based on the scale invariance of the Boltzmann equation and its collision term, the characteristics of breathing oscillations and the transition of the electron energization mechanism are confirmed to be scale-invariant under similar discharge conditions.

Classification of self-limited epilepsy with centrotemporal spikes by classical machine learning and deep learning based on electroencephalogram data

Electroencephalogram (EEG) has been widely utilized as a valuable assessment tool for diagnosing epilepsy in hospital settings. However, clinical diagnosis of patients with self-limited epilepsy with centrotemporal spikes (SeLECTS) is challenging due to the presence of similar abnormal discharges in EEG displays compared to other types of epilepsy (non-SeLECTS) patients. To assist the diagnostic process of epilepsy, a comprehensive classification study utilizing machine learning or deep learning techniques is proposed. In this study, clinical EEG was collected from 33 patients diagnosed with either SeLECTS or non-SeLECTS, aged between 3 and 11 years. In the realm of classical machine learning, sharp wave features (including upslope, downslope, and width at half maximum) were extracted from the EEG data. These features were then combined with the random forest (RF) and extreme random forest (ERF) classifiers to differentiate between SeLECTS and non-SeLECTS. Additionally, deep learning was employed by directly inputting the EEG data into a deep residual network (ResNet) for classification. The classification results were evaluated based on accuracy, F1-score, area under the curve (AUC), and area under the precision-recall curve (AUPRC). Following a 10-fold cross-validation, the ERF classifier achieved an accuracy of 73.15 % when utilizing sharp wave feature extraction for classification. The F1-score obtained was 0.72, while the AUC and AUPRC values were 0.75 and 0.63, respectively. On the other hand, the ResNet model achieved a classification accuracy of 90.49 %, with an F1-score of 0.90. The AUC and AUPRC values for ResNet were found to be 0.96 and 0.92, respectively. These results highlighted the significant potential of deep learning methods in SeLECTS classification research, owing to their high accuracy. Moreover, feature extraction-based methods demonstrated good reliability and could assist in identifying relevant biological features of SeLECTS within EEG data.

Collector probe analysis of tungsten transport to the far-SOL from the DIII-D SAS-VW divertor experiment

Experimental results from the 2022 tungsten (W)-coated Small Angle Slot (SAS-VW) divertor campaign at DIII-D coupled with interpretive 3DLIM modelling show opposing trends for core impurity content when compared to impurity deposition on far-Scrape Off Layer (SOL) Collector Probes (CPs) with increasing main ion density. SAS-VW is a closed, W-coated divertor designed to more easily facilitate divertor detachment while reducing impurity leakage. An experiment performed a series of upper-single-null L-mode discharges in each toroidal magnetic field (BT) direction, with increasing main ion density (line-averaged density = 3.15–4.35e19 m−3) that approaches and slightly exceeds the divertor detachment threshold. The results indicate: a) increased radial W transport with decreasing peak Te,tLP; and b) negligible change in W content in the far-SOL at the outer mid-plane with the onset of divertor detachment.Preliminary W deposition measurements using double-sided, graphite CPs inserted at the Midplane Materials Evaluation System (MiMES) reveal a 75% decrease over the density scan when operating in the unfavorable (ion B×∇B out of the divertor) BT direction. In contrast, soft X-ray (SXR) radiation from the same discharges is used as a proxy for W core contamination, showing core W content that increases by 77% with increasing line-averaged density. Similar L-mode discharges conducted in the favorable BT direction result in significantly less deposition on CPs.Using an interpretive modeling workflow following Zamperini 2022 [1] for assessing the transport of W sputtered from the SAS-VW divertor, the analysis suggests that W migration to the main chamber surfaces during the campaign may also contribute to far-SOL deposition.

Similarity-based scaling networks for capacitive radio frequency discharge plasmas

We demonstrate similarity-based scaling networks for capacitive radio frequency (RF) plasmas, which extensively correlate discharge characteristics under varied conditions, incorporating the transition from original to similarity states. Based on fully kinetic particle-in-cell simulations, similar RF discharges in argon are demonstrated with three external control parameters (gas pressure, gap distance, and driving frequency) simultaneously tuned. A complete set of scaling pathways regarding fundamental discharge parameters is obtained, from which each plasma state finds its neighboring node with only one control parameter tuned. The results from this study provide a promising strategy for plasma multi-parameter mapping, enabling effective cross-comparisons, prediction, and manipulation of RF discharge plasmas.

Enhanced confinement induced by pellet injection in the stellarator TJ-II

Enhanced confinement is observed in neutral beam injector (NBI)-heated hydrogen discharges made in the stellarator TJ-II after the injection of a single cryogenic fuel pellet into the plasma core. In addition to the expected increase in electron density, ne, in the core after pellet injection (PI), the plasma diamagnetic energy content is seen to rise, with respect to similar discharges without PI, by up to 40%. Furthermore, the energy confinement time, τEdiag, as determined using a diamagnetic loop, is enhanced when compared to predictions obtained using the International Stellarator Scaling law [H. Yamada et al., Nucl. Fusion 45, 1684 (2005)] and the triple product, ne · Ti · τEdiag, exhibits a clear bifurcation point toward an improved confinement branch as compared to the branch product predicted by this scaling law. In general, once such a pellet-induced enhanced confinement (PiEC) phase has been established, it is characterized by steepened radial density gradients, by more negative plasma potential in the core, more negative radial electric fields, Er, across a broad plasma region, as well as by reductions in density and plasma potential fluctuations in the density gradient region. In addition, experimental observations show increased peaking of core radiation losses, this pointing to edge/core plasma decoupling. In parallel, neoclassical simulations of reference and PiEC plasmas predict increased particle and energy confinement times during a PiEC phase together with a more negative Er profile. Qualitative rather than quantitative agreement with experimental parameters is found, indicating that turbulence seems to play a significant role here. In summary, single cryogenic pellet injection facilitates the achievement of an enhanced operational regime that was previously not observed in NBI-heated discharges of the TJ-II.

The Flocculation State of Mud in the Lowermost Freshwater Reaches of the Mississippi River: Spatial Distribution of Sizes, Seasonal Changes, and Their Impact on Vertical Concentration Profiles

AbstractWe use in situ measurements of suspended mud to assess the flocculation state of the lowermost freshwater reaches of the Mississippi River. The goal of the study was to assess the flocculation state of the mud in the absence of seawater, the spatial distribution of floc sizes within the river, and to look for seasonal differences between summer and winter. We also examine whether measured floc sizes can explain observed vertical distributions of mud concentration through a Rouse profile analysis. Data were collected at the same locations during summer and winter at similar discharges and suspended sediment concentrations. Measurements showed that the mud in both seasons was flocculated and that the floc size could reasonably be represented by a cross‐sectional averaged value as sizes varied little over the flow depth or laterally across the river at a given station. Depth‐averaged floc sizes ranged from 75 to 200 microns and increased slightly moving downriver as turbulence levels dropped. On average, flocs were 40 microns larger during summer than in winter, likely due to enhanced microbial activity associated with warmer water. Floc size appeared to explain vertical variations in mud concentration profiles when the bed was predominately composed of sand. Average mud settling velocities for these cases ranged from 0.1 to 0.5 mm/s. However, Rouse‐estimated settling velocities ranged from 1 to 3 mm/s at two stations during winter where the bed was composed of homogeneous mud. These values exceeded the size‐based estimates of settling velocity.

Ultra-fast development of Ar 2p relative densities in nanosecond-pulsed barrier discharge in argon

A time-correlated single photon counting based optical emission spectroscopy technique is applied for an investigation of the nanosecond-pulsed barrier discharge in atmospheric pressure argon gas. We record the development of the light intensities originating from all ten Ar 2p (Paschen notation) radiative states with high spatio-temporal resolution. We identify different stages of the discharge development: an early rapid electron avalanching, streamer propagation phase, generation of discharge channel and surface streamer propagation over the dielectric surface. The quantified relative 2p densities for identified discharge phases enable a well-resolved insight into the ultra-fast discharge kinetics and open a possibility for the development of future detailed diagnostics of the rapidly ionized argon plasmas. Moreover, the electrical characterization of the discharge is made using the simplest equivalent circuit and it reveals new findings for the application of such an approach for similar discharges.

Contemporary international Law:Regulating the upcoming fukushima radioactive wastewater discharge

In April 2021, the Japanese government decided to release tonnes of radioactive wastewater from the wrecked Fukushima nuclear power plant into the ocean, a decision that will likely to pose a direct threat to the marine environment of not only Japan, but also the jurisdictional waters of neighboring countries. Legal measures such as litigation against Japan has been an option for the neighboring countries, although they require more time than available, unless interim measure are ordered. Based on a multidisciplinary research approach that integrates open-source research data, authoritative data and conclusions, this paper shows that since the ocean is a complex and changeable system and radionuclides could be redistributed by the ocean currents and eddies, the radioactive wastewater discharge will cause or likely to cause contamination in fish products and fishing grounds and have negative impact on marine life and humans. In response to the widely known skepticism regarding the application and efficiency of international law concerning the 2011 Fukushima Daichii accident, this paper argues that the nuclear law, ocean law and general principles of international law do provide sufficient constraints on the forthcoming radioactive wastewater discharge. Among the IAEA's legal documents, the Convention on Nuclear Safety (CNS) and the Convention on Early Notification are the most applicable conventions to the Fukushima radioactive wastewater discharge. Treaty interpretation of the “at sea” element in the London Dumping Convention and its Protocol is crucial to determine the legitimacy of the planned oceanic discharge activity of Japan. In addition, legal characterization of sources of pollution, the place in which the oceanic discharge activity occurred and Japan's substantive and procedural obligation under the United Nations Convention on the Law of the Sea (UNCLOS) will also affect the treaty application in the forthcoming oceanic discharge. This paper proposes that for the international community as a whole, long term (regional and global cooperation) and short-term measures (inter-State cooperation) need to be taken into consideration in order to tackle Japan's decision as well as laying the framework for any similar discharges that could follow Japan's example.

Comparing alternative conceptual models for tile drains and soil heterogeneity for the simulation of tile drainage in agricultural catchments

• The seepage node concept was used to simulate tile drainage at the catchment scale. • Tile drainage was simulated without the specific location of tile drains. • Similar drainage discharge volumes were simulated with different conceptual models. • Drainage discharge was sensitive to soil heterogeneity. • Observed stream discharge and depth to water table were well simulated. Tile drains are important water flow paths in agricultural catchments and must be included in hydrological models. However, their locations are rarely known and the explicit incorporation of tile drains in hydrological models requires refined meshes around the drains, which can significantly increase computational times. Although seepage nodes have been used to represent tile drains with satisfactory performance, they have never been applied to represent all tile drainage systems in a catchment. The goal of this study is to compare different conceptual models for tile drains and soil heterogeneity for the numerical simulation of tile drainage in an agricultural catchment in Denmark. The first conceptual model for tile drains uses seepage nodes to represent only the main collector drains in the catchment and the second model uses seepage nodes distributed over all the agricultural areas, without considering the specific locations of tile drains. A third conceptual model, labelled the Benchmark Model, represent all tile drains at their known locations with seepage nodes and a fourth conceptual model implicitly represents tile drains as a high-permeability layer. The four models performed satisfactorily to simulate the observed outlet stream discharge and could be recommended almost interchangeably. The simulation of the water table depth was very satisfactory compared to modeling studies with similar mesh resolution (∼50 m). Results indicated that the three models using seepage nodes i) simulated similar monthly discharges and cumulative discharge volumes for most of the studied tile-drained areas, and ii) simulated surface water flow in tile-drained fields without runoff or ponding water. The shorter simulation times (around 35% faster) of the model representing the main drains and the distributed seepage node model suggest that they are suitable for model calibration, compared to the Benchmark Model. Whenever the location of tile drains is unavailable, using seepage node to represent drains in agricultural areas may satisfactorily simulate catchment-scale stream and drainage discharges. Four alternative soil models were developed to evaluate the effect of soil heterogeneity on the simulations. Our results suggest that at smaller scales (drainage area) soil heterogeneity is more relevant than the drainage conceptualization to improve model results. However, at the subcatchment scale, the opposite was observed and, at the catchment scale, both criteria had a comparable effect.

Improvement on Faraday rotation measurement affected by the stray lights on the HL-2A tokamak

Formic-acid (HCOOH, λ = 432.5 μm) laser P olarimeter- I nterferomet er ( PIer ) has been developed on the HL-2A tokamak, which provides 4 channels of line-integrated electron densities and 4 channels of Faraday rotation angles, respectively. Affected by the stray lights arising from the reflection of the probe waves in the optical system, the measurement of Faraday rotation angles was drastically contaminated during the HL-2A experiments, showing an obvious oscillation modulation during the electron density ramp-up/down. This paper introduces an effective correction approach used to improve the accuracy of Faraday rotation measurement on the HL-2A tokamak. Based on the method, the deviation term originating from the stray lights can be effectively subtracted from the contaminated Faraday rotation measurement. The preliminary result indicates that the interference amplitude on Faraday rotation angle is reduced by about 80%, and the corrected data is consistent with the experimental measurement by using the optical isolator that consists of a λ/4 wave-plate and polarizer under the similar discharges.

Is an extended barrier-free discharge under nanosecond-pulse excitation really diffuse?

A homogeneous discharge with a large volume is a desirable plasma source for many applications. Nanosecond-pulsed high-voltage (HV) excitation is believed to be a promising strategy for obtaining homogeneous or diffuse discharges at atmospheric pressure. In this paper, using a knife–plate geometry driven by a nanosecond-pulsed generator, a diffuse plasma sheet with a gap distance of 1 cm and a length of 12 cm is generated in atmospheric air, maintaining a low gas temperature of ∼330 K. However, time-resolved images reveal that the discharge, which appears diffuse to the naked eye, actually consists of multiple individual streamers that propagate from knife (HV) to plate (ground). The appearance of two processes, namely primary and secondary streamers, is consistently verified by discharge images, electric field evolution and fluid simulation. This further proves that the entire discharge belongs to an intermediate state between corona and spark. This work aids a deeper understanding of the intrinsic characters of similar diffuse discharges and optimizing parameters in practical applications.

The role of B T-dependent flows on W accumulation at the edge of the confined plasma

Near-separatrix impurity accumulation between the crown and the outer midplane of tokamaks is a common feature in results from codes such as SOLPS-ITER and DIVIMP; however, experimental evidence of accumulation has only recently been obtained and is reported here. The codes find that the poloidal distribution of impurity ions in the scrape-off layer (SOL) depends primarily on toroidal field (B T)-dependent parallel flow patterns of the background plasma and the parallel ion temperature gradient (∇‖ T ion) force. Experimentally, Mach probes used in L-mode plasmas with favorable (for H-mode access) B T measure fast (M ∼ 0.3–0.5) inner-target-directed (ITD) background plasma flows at the crown of single-null discharges. This study reports a set of DIVIMP simulations for two similar H-mode discharges from the DIII-D W metal rings campaign differing primarily in B T-direction to assess the effect that fast ITD flows have on the distribution of W ions in the SOL. It is found that for imposed ITD flows of M = 0.3, W ions that otherwise accumulate due to the ∇‖ T ion-force are largely flushed out. It is also found that doubling the radial diffusion coefficient from 0.3 to 0.6 m2 s−1 prevents accumulation due to rapid cross-field transport into the far-SOL, where background plasma flows drain W ions to the divertors. Far-SOL W distributions from DIVIMP are then used to specify input to the impurity transport code 3DLIM, which is used to interpretively model collector probe (CP) deposition patterns measured in the ‘wall-SOL’. It is demonstrated that the deposition patterns are consistent with the DIVIMP predictions of near-SOL accumulation for the unfavorable-B T direction, and little/no accumulation for the favorable-B T direction. The wall-SOL CPs have thus provided the first experimental evidence, albeit indirect, of near-SOL W accumulation—finding it occurs for the unfavorable-B T direction only. For the favorable-B T direction, fast flows can largely prevent accumulation from occurring.

On the scaling laws for low-temperature plasmas at macro and micro scales

The theoretical background and historical development of the similarity theory during the past decades are reviewed. We demonstrate similar discharges in local and nonlocal kinetic regimes, taking the low-pressure capacitive radio frequency (rf) discharges and microdischarges as examples. By using fully kinetic particle-in-cell simulations, we verify the similarity law (SL) and show a violation of frequency scaling (f-scaling) in the low-pressure capacitive rf plasmas. The similarity relations for electron density and electron power absorption are confirmed in similar rf discharges. With only the driving frequency varied, the f-scaling for electron density is also validated, showing almost the same trend as the similarity scaling, across most of the frequency regime. However, violations of the f-scaling are observed at lower frequencies, which are found to be relevant to the electron heating mode transition from stochastic to Ohmic heating. The scaling characteristics have also been comprehensively studied for microdischarges with dimensions from hundreds to several microns, with transition from secondary electron dominated regime to field emission regime. Finally, practical applications of the similarity and scaling laws are summarized.

A combined actinometry approach for medium pressure N2–O2 plasmas

An argon actinometry approach which uses the 777 nm and 844 nm atomic oxygen lines along with the common N2/ line ratio method is used to experimentally investigate the excitation mechanisms of the O(3p5P) state in medium pressure (0.75 Torr) N2–O2 plasmas. The method provides strong evidence that metastable excitation from the O(3s5S◦) state is an important excitation mechanism for O(3p5P) state for these conditions. The strong dependence of this additional mechanism on electron density along with the use of the N2/ line ratio method allow for the simultaneous determination of effective electron temperature, dissociation fraction, metastable O(3s5S◦) density and electron density. Predicted electron temperatures, electron densities and dissociation fractions are consistent with those found for similar discharges in prior studies. Additionally, we investigate the efficacy of using the observed 616 nm atomic oxygen line from the O(4d5D◦) state for actinometry, which could open the door to a novel and comprehensive actinometry technique.

Plasma treatment of spruce wood changes its dielectric properties

The effects of dielectric barrier discharge (DBD) plasma treatment on the dielectric properties of Norway spruce wood (Picea abies (L.) Karst.) were investigated using dielectric analysis. Dielectric constant (i.e. permittivity) and loss coefficient were determined at various frequencies. The resulting changes on lamellae specimens of different thicknesses were compared with the change in mass and moisture content. A significant influence of the plasma was found, leading to an increase of the dielectric constant by about 2%, and a decrease of sample mass directly after the plasma treatment by approx. 14%, whereas a reduction in moisture content by only about 0.6% and a corresponding change in loss coefficient were detected. Overall, the mechanisms of the observed changes remain unclear and seem mainly uncorrelated with the hitherto known chemical changes in wood surfaces caused by similar plasma discharges.

Similarity law and frequency scaling in low-pressure capacitive radio frequency plasmas

We verify the similarity law (SL) and show a violation of frequency scaling (f-scaling) in low-pressure capacitive radio frequency (rf) plasmas via fully kinetic particle-in-cell simulations. The SL scaling relations for electron density and electron power absorption are first confirmed in similar rf discharges. Based on these results, with only the driving frequency varied, the f-scaling for electron density is also validated, showing almost the same trend as the SL scaling, across most of the frequency regime. However, violations of the f-scaling are observed at lower frequencies, which are found to be relevant to the electron heating mode transition from stochastic to Ohmic heating. Electron kinetic invariance is illustrated for the SL and f-scaling being valid, respectively, whereas the electron kinetic variation is observed when the f-scaling is violated.

Similarity of capacitive radio-frequency discharges in nonlocal regimes

Similarity transformations are essential for correlating discharges at different scales, which are mostly utilized with local field or local energy approximations. In this work, we report the fully kinetic results from particle-in-cell/Monte Carlo collision simulations that unambiguously demonstrate the similarity of radio frequency (rf) discharges in nonlocal regimes where the electron energy relaxation length is much larger than the gap dimension. It is found that at a constant rf voltage amplitude, discharges will be similar if the gas pressure, inverse of gap distance, and rf driving frequency are all changed by the same scaling factor. The scaling relations of fundamental parameters are illustrated for rf discharges in the alpha-mode with secondary electron emission ignored, and the temporal electron kinetics are shown to have invariance in similar discharges. The results explicitly validate the scaling laws in nonlocal kinetic regimes, indicating promising application potentials of the similarity transformations across a wide range of kinetic regimes.

Sleep and Epilepsy Link by Plasticity.

We aimed to explore the link between NREM sleep and epilepsy. Based on human and experimental data we propose that a sleep-related epileptic transformation of normal neurological networks underlies epileptogenesis. Major childhood epilepsies as medial temporal lobe epilepsy (MTLE), absence epilepsy (AE) and human perisylvian network (PN) epilepsies - made us good models to study. These conditions come from an epileptic transformation of the affected functional systems. This approach allows a system-based taxonomy instead of the outworn generalized-focal classification. MTLE links to the memory-system, where epileptic transformation results in a switch of normal sharp wave-ripples to epileptic spikes and pathological high frequency oscillations, compromising sleep-related memory consolidation. Absence epilepsy (AE) and juvenile myoclonic epilepsy (JME) belong to the corticothalamic system. The burst-firing mode of NREM sleep normally producing sleep-spindles turns to an epileptic working mode ejecting bilateral synchronous spike-waves. There seems to be a progressive transition from AE to JME. Shared absences and similar bilateral synchronous discharges show the belonging of the two conditions, while the continuous age windows - AE affecting schoolchildren, JME the adolescents - and the increased excitability in JME compared to AE supports the notion of progression. In perisylvian network epilepsies - idiopathic focal childhood epilepsies and electrical status epilepticus in sleep including Landau-Kleffner syndrome - centrotemporal spikes turn epileptic, with the potential to cause cognitive impairment. Postinjury epilepsies modeled by the isolated cortex model highlight the shared way of epileptogenesis suggesting the derailment of NREM sleep-related homeostatic plasticity as a common step. NREM sleep provides templates for plasticity derailing to epileptic variants under proper conditions. This sleep-origin explains epileptiform discharges' link and similarity with NREM sleep slow oscillations, spindles and ripples. Normal synaptic plasticity erroneously overgrowing homeostatic processes may derail toward an epileptic working-mode manifesting the involved system's features. The impact of NREM sleep is unclear in epileptogenesis occurring in adolescence and adulthood, when plasticity is lower. The epileptic process interferes with homeostatic synaptic plasticity and may cause cognitive impairment. Its type and degree depends on the affected network's function. We hypothesize a vicious circle between sleep end epilepsy. The epileptic derailment of normal plasticity interferes with sleep cognitive functions. Sleep and epilepsy interconnect by the pathology of plasticity.