The Naval Research Laboratory three‐dimensional simulation code SAMI3/ESF is used to study the response of postsunset ionosphere circular gravity waves. We model coupling both (local) and plane wave (nonlocal) waves bottomside F layer as a mechanism for triggering equatorial plasma bubbles. Results support hypothesis that nonplane can more strongly couple than also show seed depends on growth rate local electron density at position wave.

A new low‐latitude ionospheric model has been developed at the Naval Research Laboratory: Sami2 is Another Model of Ionosphere (SAMI2). SAMI2 treats dynamic plasma and chemical evolution seven ion species (H + , He N O 2 NO ) in altitude range ∼ 100 km to several thousand kilometers. The continuity momentum equations are solved for all species; temperature equation H electrons. models along Earth's dipole field from hemisphere hemisphere, includes E × B drift a flux tube (both longitude),...

An electron acceleration method is investigated which employs a short (τL ∼2πωω−1p ∼1 ps), high-power (P≥1015 W), single frequency laser pulse to generate large amplitude (E≥1 GeV/m) plasma waves (wakefields). At sufficiently high powers [P≥17(ω/ωp )2 GW], relativistic optical guiding may be used prevent the from diffracting within plasma.

A two-dimensional, axisymmetric, relativistic fluid model describing the propagation of intense laser pulses in plasmas is formulated and numerically evaluated. Relativistic guiding ineffective preventing diffractive spreading short long become modulated due to wake-field effects. Laser can be propagated over many Rayleigh lengths by use a performed plasma density channel or tailoring pulse profile. Ultrahigh axial electric fields generated behind pulse.

The Naval Research Laboratory (NRL) has developed a new three‐dimensional code to study equatorial spread F (ESF). is based on the comprehensive NRL 3D ionosphere model SAMI3 and includes potential equation self‐consistently solve for electric field. assumes equipotential field lines so 2D electrodynamic problem considered. In this narrow wedge of post‐sunset simulated. It found that (1) bubbles can rise ∼1600 km, (2) extremely steep ion density gradients develop in both longitude latitude,...

[1] Recent ionospheric observations indicate that the total electron content (TEC) may anomalously decrease or increase up to 5–20% before occurrence of big earthquakes. The density variations can be caused by earth surface charges/currents produced from electric currents associated with stressed rock. We formulate a coupling model for rock-Earth charges-atmosphere-ionosphere system. stressed-rock acts as dynamo provide fields and in atmosphere lower boundary ionosphere are obtained solving...

Land use land cover (LULC) change is one of the major driving forces global environmental in many developing countries. In this study, LULC changes were evaluated Gaborone dam catchment Botswana between 1984 and 2015. The a source water supply to city its surrounding areas. study employed Remote Sensing Geographical Information System (GIS) using Landsat imagery 1984, 1995, 2005 Image classification for each these imageries was done through supervised Maximum Likelihood Classifier. Six...

Land use/land cover (LULC) changes have been observed in the Gaborone dam catchment since 1980s. A comprehensive analysis of future LULC is therefore necessary for purposes land use and water resource planning management. Recent advances geospatial modelling techniques availability remotely sensed data become central to monitoring assessment both past environmental changes. This study employed cellular automata Markov chain (CA-Markov) model combinations simulate catchment. Classified...

The laser wake-field acceleration concept is studied using a general axisymmetric formulation based on relativistic fluid equations. This formalism valid for arbitrary intensities and allows the laser–plasma interaction to be simulated over long propagation distances (many Rayleigh lengths). Several methods optically guiding pulse are examined, including guiding, preformed plasma density channels tailored profiles. Self-modulation of laser, which occurs when length compared wavelength power...

We report the experimental discovery of "electrorheological (ER) complex plasmas," where control interparticle interaction by an externally applied electric field is due to distortion Debye spheres that surround microparticles (dust) in a plasma. show interactions ER plasmas under weak ac fields are mathematically equivalent those conventional fluids. Microgravity experiments, as well molecular dynamics simulations, phase transition from isotropic anisotropic (string) plasma state increased.

Far field effective potential of charged particle in Vlasov plasma, discussing inverse third power law for shielding test particles

view Abstract Citations (103) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Formation of the 0.511 MeV line in solar flares. Crannell, C. J. ; Joyce, G. Ramaty, R. Werntz, The slowing down and annihilation positrons formation positronium a flare plasma are investigated to determine how width 0.511-MeV its strength relative three-photon continuum from decay depend on temperature density medium which positron comes rest. calculations limited...

The NRL three‐dimensional ionospheric simulation code SAMI3 is used to model the onset and evolution of equatorial spread F (ESF). a comprehensive ionosphere that has been modified self‐consistently solve for global neutral wind driven dynamo electric field as well gravity associated with plasma bubbles. latter achieved high resolution longitudinal grid in pre‐ post‐sunset sector (i.e., 1630 MLT–2230 MLT). Initial results from new are presented. It shown ESF can be triggered by pre‐sunset...

The first self‐consistent study of the impact storm‐time penetration electric fields on low‐ to mid‐latitude ionosphere is presented. inner magnetosphere described by Rice Convection Model (RCM) and Naval Research Laboratory (NRL) code SAMI3. codes are coupled electrodynamically through electrostatic potential equation, storm modeled via changes in polar cap potential. Neutral wind driven estimated from Fejer/Scherliess quiet time model. It found that temporal produce modify F region...

The force on a charged test particle embedded in flowing (electron-ion) plasma is calculated using the linear dielectric response formalism. This approach allows us to take into account ion-neutral collisions self-consistently. effect of ion drag analyzed. It shown that can play major role and enhance substantially.

We present a numerical study of the propagation VLF whistler waves in magnetospheric plasma. In this plasma is considered to be homogeneous direction along ambient magnetic field and strongly inhomogeneous across it. The goal investigation understand magnetic‐field‐aligned channels (also called ducts) with either enhanced or depleted density. particular, paper focused on situations where transverse scale size duct comparable smaller than perpendicular wavelength whistler. case, classical...

The NRL SAMI3/ESF three‐dimensional simulation code is used to examine the effect of zonal neutral winds on dynamics and morphology equatorial spread F (ESF). Three wind models are used: (a) a constant eastward 150 m/s, (b) HWM93, (c) HWM07. It shown that ESF bubbles depends strongly wind. results compared with TIMED/GUVI IMAGE/FUV data. For conditions studied (F10.7 = 170) it found HWM93 model agree better data than those from or Specifically, observations reversed ‘C’ shaped FUV image,...

The interaction of a tenuous energetic test-particle species with multispecies high temperature plasma is calculated. Balescu-Lenard kinetic equation used in order to include collective effects through the dielectric constant. Quantum corrections are made for close collisions. theory first applied slowing down fusion born alpha particles mirror-confined and numerical results compared previous treatments found. In Tokamak-like plasmas most alpha-particle energy goes into electrons...

A method for up-shifting the frequency of a subpicosecond laser pulse that utilizes interaction with co-propagating relativistic ionization front is examined. The induced shift found to initially scale linearly propagation time \ensuremath{\tau}. Asymptotically, scales as ${\mathrm{\ensuremath{\tau}}}^{1/2}$. Phase-slippage limitations may be overcome by appropriately increasing plasma density function \ensuremath{\tau}, thus allowing substantially higher-frequency shifts.

Melting of a monolayer plasma crystal in radio-frequency discharge with no particles suspended above or below is studied. The experimental data are compared results molecular dynamics simulations and theory. It shown that the melting caused by resonance coupling between longitudinal transverse dust-lattice wave modes, due to interaction wakes.

In a plasma with ions streaming at uniform velocity /spl sim/c/sub s/, dust grains can be accurately modeled as particles interacting via the dynamically-screened Coulomb interaction, calculated from linear response theory for plasma. This force is nonreciprocal, i.e., action does not equal reaction, which has remarkable dynamical consequences. We show that up to four form stable self-bound molecule, propels itself upstream against ion flow. Stable equilibria are also found pairs of confined...

Abstract. The NRL SAMI3 three-dimensional simulation code is used to examine the effect of meridional winds on growth and suppression equatorial spread F (ESF). geometry conforms a dipole field with field-line apex heights from 200 1600 km at equator, but extends over only 4 degrees in longitude. full ionosphere equations are included, providing ion dynamics both along across field. potential solved two dimensions plane under equipotential approximation. By selectively including terms...

The Naval Research Laboratory has recently developed a new two‐dimensional code to study equatorial spread F (ESF): NRLESF2. uses an 8th order spatial interpolation scheme and the partial donor cell method. This allows model capture very sharp gradients over ∼ 4 grid cells assess impact of numerical diffusion on dynamics ‘bubble’ evolution. Simulation results are presented that show complex ESF bubble dynamics: multiple bifurcations, secondary instabilities, density ‘bite‐outs’ three orders...

The Naval Research Laboratory (NRL) three‐dimensional simulation code SAMI3/ESF is used to study the long time evolution of equatorial spread F (ESF) bubbles. ESF bubbles are modeled until they stop rising and become “fossils,” with results analyzed address previously‐untested hypotheses. Specifically, it has been suggested that when either local electron density inside bubble equal nearby background or flux‐tube‐integrated background. It shown magnetic ion mass equals surrounding...

Dedicated experiments with strongly coupled complex plasmas in external electric fields were carried out under microgravity conditions using the PK-4 dc discharge setup. The focus was put on comparative analysis of formation stringlike anisotropic structures due to reciprocal (hamiltonian) and nonreciprocal (non-hamiltonian) interactions between microparticles (induced by ac fields, respectively). complemented numerical simulations demonstrate that responses these two regimes are drastically...