Effect of change in large and fast solar wind dynamic pressure on geosynchronous magnetic field

We present a comparison of changes in large and sharp solar wind dynamic pressure, observed by several spacecraft, with fast disturbances in the magnetospheric magnetic field, measured by the geosynchronous satellites. More than 260 changes in solar wind pressure during the period 1996-2003 are selected for this study. Large statistics show that an increase （a decrease） in dynamic pressure always results in an increase （a decrease） in the magnitude of geosynchronous magnetic field. The amplitude of response to the geomagnetic field strongly depends on the location of observer relative to the noon meridian, the value of pressure before disturbance, and the change in amplitude of pressure.

Joint observations of the large-scale ULF wave activity from space to ground associated with the solar wind dynamic pressure enhancement

This study reports the rare ultralow-frequency(ULF) wave activity associated with the solar wind dynamic pressure enhancement that was successively observed by the GOES-17(Geostationary Operational Environmental Satellite) in the magnetosphere, the CSES(China Seismo-Electromagnetic Satellite) in the ionosphere, and the THEMIS ground-based observatories(GBO) GAKO and EAGL in the Earth's polar region during the main phase of an intense storm on 4 November 2021. Along with the enhanced-pressure solar wind moving tailward, the geomagnetic field structure experienced a large-scale change. From dawn/dusk sides to midnight, the GAKO, EAGL, and GOES-17 sequentially observed the ULF waves in a frequency range of0.04–0.36 Hz at L shells of ~5.07, 6.29, and 5.67, respectively. CSES also observed the ULF wave event with the same frequency ranges at wide L-shells of 2.52–6.22 in the nightside ionosphere. The analysis results show that the ULF waves at ionospheric altitude were mixed toroidal-poloidal mode waves. Comparing the ULF waves observed in different regions, we infer that the nightside ULF waves were directly or indirectly excited by the solar wind dynamic pressure increase: in the area of L-shells~2.52–6.29, the magnetic field line resonances(FLRs) driven by the solar wind dynamic pressure increase is an essential excitation source;on the other hand, around L~3.29, the ULF waves can also be excited by the outward expansion of the plasmapause owing to the decrease of the magnetospheric convection, and in the region of L-shells ~5.19–6.29, the ULF waves are also likely excited by the ion cyclotron instabilities driven by the solar wind dynamic pressure increase.

A repeated interdiffusion method for efficient planar formamidinium perovskite solar cells

A repeated interdiffusion method is described for phase-stable and high-quality （FA,MA）PbI3 film. The crys- tallization and growth of the perovskite films can be well controlled by adjusting the reactant concentrations. With this method, dense, smooth perovskite films with large crystals have been obtained. Finally, a PCE of 16.5% as well as a steady-state efficiency of 16.3% is achieved in the planar perovskite solar cell.

Kinematics of solar neighborhood stars and its dependence on age and metallicity

We have constructed a catalog containing the best available astrometric, photometric, radial velocity and astrophysical data for mainly F-type and G-type stars （called the Astrometric Catalog associated with Astrophysical Data, ACAD）. This contains 27 553 records and is used for the purpose of analyzing stellar kinematics in the solar neighborhood. Using the Lindblad-Oort model and compiled ACAD, we calculated the solar motion and Oort constants in different age-metallicity bins. The evolution of kinematical parameters with stellar age and metallicity was investigated directly. The results show that the component of the solar motion in the direction of Galactic rotation （denoted S_2） linearly increases with age, which may be a conse- quence of the scattering processes, and its value for a dynamical cold disk was found to be 8.0 ± 1.2 km s^-1. S_2 also linearly increases with metallicity, which indicates that radial migration is correlated to the metallicity gradient. On the other hand, the rotational velocity of the Sun around the Galactic center has no clear correlation with ages or metallicities of stars used in the estimation.

Post-noon ionospheric absorption observed by the imaging riometers at polar cusp/cap conjugate stations

An example of post-noon ionospheric absorption observed by the imaging riometers at Ny-Alesund / Danmarkshavn in the arctic region and Zhongshan Station in Antarctic is presented. The post-noon absorption observed simultaneously between the hemispherical stations was a spike-type with weak intensity (<1 dB) during the high solar wind dynamic pressure. The absorption spikes might be caused by precipitation of highrenergy electrons (30 - 300 keV) in the closed dayside magnetosphere. It should be noted that the precipitation region of the absorption spike associated with the steep pressure increase (~ 13 nPa) was localized and shifted equatorward.

Velocity Space of Galactic O-B Stars

Based on the Hipparcos proper motions and available radial velocity data of O-B stars, we have re-examined the local kinematical structure of the young disk population of 1500 O-B stars not including the Gould-belt stars. A systematic warping motion of the stars about the direction to the Galactic center has been reconfirmed. A negative K-term implying a systematic contraction of stars in the solar vicinity has been detected. Two different distance scales are used in order to find out their impact on the kinematical parameters, and we conclude that the adopted distance scale plays an important role in characterizing the kinematical parameters at the present level of the measurement uncertainty.

Three-Dimensional Heat Transfer Analysis for A Thermal Energy Storage Canister

High temperature latent thermal storage is one of the critical techniques for a solar dynamic power system. This paper presents results from heat transfer analysis of a phase change salt containment canister A three-dimensional analysis program is developed to model heat transfer in a PCM canister. Analysis include effects of asymmetric circumference heat flux, conduction in canister walls, liquid PCM and solid PCM, void volume change and void location, and conduction and radiation across PCM vapor void. The PCM phase change process is modeled using the enthalpy method and the simulation results are compared with those of other two- dimensional investigations. It’s shown that there are large difference with two-dimensional analysis, therefore the three-dimensional model is necessary for system design of high temperature latent thermal storage.

Compression-related EMIC waves drive relativistic electron precipitation

With coordinated observations of the NOAA 15 satellite and OUL magnetometer station in Finland, we report that the elec- tromagnetic ion cyclotron （EMIC） waves which were stimulated by the compression of the magnetosphere drive relativistic electron precipitation in geoquiescence on 1 Jan 2007. After an enhancement of solar wind dynamic pressure （SWDP）, a day- side Pcl pulsation was observed by the OUL station. Such a Pcl pulsation is caused by an EMIC wave which propagates from the generation source to lower altitudes. Simultaneously, the NOAA 15 satellite registered an enhancement of precipitating electron count rates with energies 〉3 MeV within the anisotropic zone of protons. This phenomenon is coincident with the quasi-linear theoretical calculation presented in this paper. Our observations suggest that after a positive impulse of solar wind, the compression-related EMIC waves can drive relativistic electrons precipitation and play a pivotal role in the dynamic of ra- diation belts.