One-dimensional analysis is presented of solitary positive potential plasma structures whose velocity lies within the range of ion distribution velocities that are strongly populated: "slow" electron holes. It is shown that to avoid the self-acceleration of the hole velocity away from ion velocities it must lie within a local minimum in the ion velocity distribution. Quantitative criteria for the existence of stable equilibria are obtained. The background ion distributions required are generally stable to ion-ion modes unless the electron temperature is much higher than the ion temperature. Since slow positive potential solitons are shown not to be possible without a significant contribution from trapped electrons, it seems highly likely that such observed slow potential structures are indeed electron holes.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevE.104.015208 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
The sluggish water oxidation reaction (WOR) is considered the kinetic bottleneck of artificial photosynthesis due to the complicated four-electron and four-proton transfer process. Herein, we find that the WOR can be kinetically nearly barrierless on four representative photoanodes (i.e.
View Article and Find Full Text PDFAdv Mater
January 2025
College of Environment and Climate, Guangdong Provincial Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China.
Combining piezocatalysts with mechanical ball milling for dissociating water to generate hydroxyl radicals (·OH) offers unprecedented opportunities for energy conversion and environmental remediation. However, the in-depth insights into the relationship between water and local polarization piezoelectric electric field (LPPEF) are currently lacking, in particularly, the ·OH formation mechanism in ball milling driven piezocatalyst system is not systematically elucidated. To this end, the present work constructs a ball milling driven piezoelectric solid/liquid interface between piezoelectric PbBOCl (PBOC) and different contents of water to investigate LPPEF initiated catalytic reaction.
View Article and Find Full Text PDFNature
January 2025
Southwest Research Institute, San Antonio, TX, USA.
Chorus waves are some of the strongest electromagnetic emissions naturally occurring in space and can cause radiation that is hazardous to humans and satellites. Although chorus waves have attracted extreme interest and been intensively studied for decades, their generation and evolution remain highly debated. Here, in contrast to the conventional expectation that chorus waves are governed by planetary magnetic dipolar fields, we report observations of repetitive, rising-tone chorus waves in the terrestrial neutral sheet, where the effects of the magnetic dipole are absent.
View Article and Find Full Text PDFSci Rep
January 2025
Accelerator Operations and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545, USA.
The pursuit to operate photocathodes at high accelerating gradients to increase brightness of electron beams is gaining interests within the accelerator community, particularly for applications such as free electron lasers (FEL) and compact accelerators. Cesium telluride (CsTe) is a widely used photocathode material and it is presumed to offer resilience to higher gradients because of its wider band gap compared to other semiconductors. Despite its advantages, crucial material properties of CsTe remain largely unknown both in theory and experiments.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Analysis and Testing Center, Xinyang University, Xinyang 464000 China. Electronic address:
A significant enhancement in the photocatalytic activity of metal-organic frameworks (MOFs) is achieved by expanding the visible-light response range through the strategic incorporation of functional groups, such as metalloporphyrins. Herein, Pd-metalised tetrakis(4-carboxyphenyl)porphyrin (PdTCPP) photosensitiser is integrated into the UiO-66-(NH) framework, creating the hybrid material PdTCPP ⊂ UiO-66-(NH) using a facile mixed-ligand strategy. Platinum nanoparticles (Pt NPs) are subsequently introduced as a co-catalyst via in situ photoreduction, resulting in the formation of the Pt/PdTCPP ⊂ UiO-66-(NH) hybrid material, which demonstrates exceptional catalytic performance under visible-light irradiation.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!