Explore the vast range of titles available.

Launched on 12 Aug. 2018, NASA’s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission’s primary science goal is to determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number of discoveries reported in nearly 700 peer-reviewed publications. The first four years of the 7-year primary mission duration have been mostly during solar minimum conditions with few major solar events. Starting with orbit 8 (i.e., 28 Apr. 2021), Parker flew through the magnetically dominated corona, i.e., sub-Alfvénic solar wind, which is one of the mission’s primary objectives. In this paper, we present an overview of the scientific advances made mainly during the first four years of the Parker Solar Probe mission, which go well beyond the three science objectives that are: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles.

Spicules are rapidly evolving fine-scale jets of magnetized plasma in the solar chromosphere. It remains unclear how these prevalent jets originate from the solar surface and what role they play in heating the solar atmosphere. Using the Goode Solar Telescope at the Big Bear Solar Observatory, we observed spicules emerging within minutes of the appearance of opposite-polarity magnetic flux around dominant-polarity magnetic field concentrations. Data from the Solar Dynamics Observatory showed subsequent heating of the adjacent corona. The dynamic interaction of magnetic fields (likely due to magnetic reconnection) in the partially ionized lower solar atmosphere appears to generate these spicules and heat the upper solar atmosphere.

Concentrating solar power (CSP) technology is poised to take its place as one of the major contributors to the future clean energy mix. Using straightforward manufacturing processes, CSP technology capitalises on conventional power generation cycles, whilst cost effectively matching supply and demand though the integration of thermal energy storage. Concentrating solar power technology provides a comprehensive review of this exciting technology, from the fundamental science to systems design, development and applications.Part one introduces fundamental principles of concentrating solar power systems. Site selection and feasibility analysis are discussed, alongside socio-economic and environmental assessments. Part two focuses on technologies including linear Fresnel reflector technology, parabolic-trough, central tower and parabolic dish concentrating solar power systems, and concentrating photovoltaic systems. Thermal energy storage, hybridization with fossil fuel power plants and the long-term market potential of CSP technology are explored. Part three goes on to discuss optimisation, improvements and applications. Topics discussed include absorber materials for solar thermal receivers, design optimisation through integrated techno-economic modelling, heliostat size optimisation, heat flux and temperature measurement technologies, concentrating solar heating and cooling for industrial processes, and solar fuels and industrial solar chemistry.With its distinguished editors and international team of expert contributors, Concentrating solar power technology is an essential guide for all those involved or interested in the design, production, development, optimisation and application of CSP technology, including renewable energy engineers and consultants, environmental governmental departments, solar thermal equipment manufacturers, researchers and academics. Provides a comprehensive review of concentrating solar power (CSP) technology, from the fundamental science to systems design, development and applicationsReviews fundamental principles of concentrating solar power systems, including site selection and feasibility analysis and socio-economic and environmental assessmentsProvides an overview of technologies such as linear Fresnel reflector technology, parabolic-trough, central tower and parabolic dish concentrating solar power systems, and concentrating photovoltaic systems

The magnetic field configurations associated with interplanetary coronal mass ejections (ICMEs) are the in situ manifestations of the entrained magnetic structure associated with coronal mass ejections (CMEs). We present a comprehensive study of the internal magnetic field configurations of ICMEs observed at 1 AU by the Wind mission during 1995 – 2015. The goal is to unravel the internal magnetic structure associated with the ICMEs and establish the signatures that validate a flux-rope structure. We examine the expected magnetic field signatures by simulating spacecraft trajectories within a simple flux rope, i.e. , with circular–cylindrical (CC) helical magnetic field geometry. By comparing the synthetic configurations with the 353 ICME in situ observations, we find that only 152 events ( F r ) display the clear signatures of an expected axial-symmetric flux rope. Two more populations exhibit possible signatures of flux rope; 58 cases ( F − ) display a small rotation ( < 90 ∘ ) of the magnetic field direction, interpreted as a large separation of the spacecraft from the center, and, 62 cases ( F + ) exhibit larger rotations, possibly arising from more complex configuration. The categories, C x (14%) and E events (9%), reveal signatures of complexity possibly related with evolutionary processes. We then reconstruct the flux ropes assuming CC geometry. We examine the orientation and geometrical properties during the solar activity levels at the end of Solar Cycle 22 (SC22), SC23 and part of SC24. The orientation exhibits solar cycle trends and follow the heliospheric current sheet orientation. We confirm previous studies that found a Hale cycle dependence of the poloidal field reversal. By comparing our results with the occurrence of CMEs with large angular width ( AW > 60 ∘ ) we find a broad correlation suggesting that such events are highly inclined CMEs. The solar cycle distribution of bipolar vs. unipolar B z configuration confirms that the CMEs may remove solar cycle magnetic field and helicity.

The Solar Radiation and Climate Experiment (SORCE) was a NASA mission that operated from 2003 to 2020 to provide key climate-monitoring measurements of total solar irradiance (TSI) and solar spectral irradiance (SSI). This 17-year mission made TSI and SSI observations during the declining phase of Solar Cycle 23, during all of Solar Cycle 24, and at the very beginning of Solar Cycle 25. The SORCE solar-variability results include comparisons of the solar irradiance observed during Solar Cycles 23 and 24 and the solar-cycle minima levels in 2008 – 2009 and 2019 – 2020. The differences between these two minima are very small and are not significantly above the estimate of instrument stability over the 11-year period. There are differences in the SSI variability for Solar Cycles 23 and 24, notably for wavelengths longer than 250 nm. Consistency comparisons with SORCE variability on solar-rotation timescales and solar-irradiance model predictions suggest that the SORCE Solar Cycle 24 SSI results might be more accurate than the SORCE Solar Cycle 23 results. The SORCE solar-variability results have been useful for many Sun–climate studies and will continue to serve as a reference for comparisons with future missions studying solar variability.

In recent years, China has become not just a large producer but a major market for solar photovoltaics (PV), increasing interest in solar electricity prices in China. The cost of solar PV electricity generation is affected by many local factors, making it a challenge to understand whether China has reached the threshold at which a grid-connected solar PV system supplies electricity to the end user at the same price as grid-supplied power or the price of desulfurized coal electricity, or even lower. Here, we analyse the net costs and net profits associated with building and operating a distributed solar PV project over its lifetime, taking into consideration total project investments, electricity outputs and trading prices in 344 prefecture-level Chinese cities. We reveal that all of these cities can achieve—without subsidies—solar PV electricity prices lower than grid-supplied prices, and around 22% of the cities’ solar generation electricity prices can compete with desulfurized coal benchmark electricity prices. Although solar photovoltaic use grows rapidly in China, comparison with grid prices is difficult as photovoltaic electricity prices depend on local factors. Using prefecture-level data, Yan et al. find that 100% of user-side systems can achieve grid parity, while 22% can produce electricity cheaper than coal-based power plants.

Using the 8.5‐year Venus Express measurements, we demonstrate the asymmetric plasma distributions in the Venusian magnetosheath. An escaping plume is formed by pickup oxygen ions in the hemisphere where the motional electric field points outward from Venus, while the velocity of solar wind protons is faster in the opposite hemisphere. The pickup O+ escape rate is estimated to be (3.6 ± 1.4) × 1024 s−1 at solar maximum, which is comparable to the ion loss rate through the magnetotail, and (1.3 ± 0.4) × 1024 s−1 at solar minimum. The increase of O+ fluxes with extreme ultraviolet (EUV) intensity is significant upstream of the bow shock, partially attributed to the increase of exospheric neutral oxygen density. However, the solar wind velocity just has a slight effect on the pickup O+ escape rate in the magnetosheath, while the effect of solar wind density is not observed. Our results suggest the pickup O+ escape rate is mainly controlled by EUV radiation. Plain Language Summary The atmospheric evolution and water escape of Venus might be influenced by the solar wind‐Venus interaction. The atoms outside the induced magnetosphere are ionized by the solar radiation and accelerated to the escape velocity by solar wind electric field. In this way, the oxygen ions are picked up by solar wind and lost from the atmosphere to space. We use the data from Venus Express spacecraft to analyze the distribution of pickup oxygen ions in the vicinity of the planet. The planetary oxygen ions form a strong escaping plume, indicating the pickup process is an efficient escape channel removing the atmospheric particles. With an enhanced solar extreme ultraviolet radiation, the escape rate through this channel would be higher because more ions are produced and then picked up. This indicates an enhanced ion loss billions of years ago since the young Sun is more active, which might be a reason for the disappearance of a presumably‐existed ocean. Key Points The pickup O+ escape rate at Venus increases with solar activity, and it is comparable to the ion loss rate through the magnetotail The solar wind velocity has a slight effect on the pickup O+ escape rate in the magnetosheath The neutral oxygen density upstream of the bow shock might increase by a factor of two from solar minimum to maximum

The Sun provides nearly all the energy powering the Earth’s climate system, far exceeding all other energy sources combined. The incident radiant energy, the “total solar irradiance,” has been measured by an uninterrupted series of temporally overlapping precision space-borne radiometric instruments since 1978, giving a record spanning more than four 11-year solar cycles. Short-term total-irradiance variations exceeding 0.1% can occur over a few days while variations of ~ 0.1% in-phase with the solar cycle are typical. Knowledge of solar variability on timescales longer than the current multi-decadal space-borne record relies on solar-activity proxies and models, which indicate similar-magnitude changes over centuries. Spectrally resolved space-borne irradiance measurements in the ultraviolet have been acquired continuously since 1979, while measurements contiguously spanning the near-ultraviolet to the near-infrared began in 2003. The combination of long-term total- and spectral-irradiance measurements helps determine both the solar causes of irradiance variability, which are primarily due to solar-surface magnetic-activity regions such as sunspots and faculae, and the mechanisms by which solar variability affects the Earth’s climate system, with global and regional temperatures responding to variability at solar-cycle and longer timescales. To better understand these solar influences, the most modern total-irradiance instruments are approaching the needed climate-driven measurement accuracy and stability requirements for detection of potential long-term solar-variability trends, while the latest spectral-irradiance instruments are beginning to be able to discern solar-cycle variability. Focusing on the space-borne era where such measurements are the most accurate and stable, this article describes solar-irradiance instrument designs, capabilities, and operational methodologies. It summarizes the many total- and spectral-irradiance measurements available and the measured solar variabilities on timescales from minutes to solar cycles and discusses extrapolations via models to longer timescales. Measurement composites and reference spectra are reviewed. Current capabilities and future directions are described along with the climate-driven solar-irradiance measurement requirements.

A solution-processable inorganic semiconductor is reported that can replace the liquid electrolyte of dye-sensitized solar cells, yielding all-solid-state solar cells with impressive energy conversion efficiencies. Solid progress for dye-sensitized solar cells The efficiency and low cost of dye-sensitized solar cells based on titanium dioxide make them attractive for renewable-energy applications, but the use of organic electrolytes in the device structures renders them susceptible to leakage and corrosion. Mercouri Kanatzidis and colleagues have now identified a solution-processable inorganic semiconductor consisting of CsSnI 3- x F x compounds that can replace the liquid electrolyte, yielding all-solid-state solar cells with impressive energy-conversion efficiencies, especially in the red region of the spectrum, where they outperform conventional dye-sensitized solar cells. These new compounds consist of inexpensive, Earth-abundant elements and can be processed at room temperature. With further optimization and improved dyes, much higher efficiencies should be achievable. Dye-sensitized solar cells based on titanium dioxide (TiO 2 ) are promising low-cost alternatives to conventional solid-state photovoltaic devices based on materials such as Si, CdTe and CuIn 1− x Ga x Se 2 (refs 1 , 2 ). Despite offering relatively high conversion efficiencies for solar energy, typical dye-sensitized solar cells suffer from durability problems that result from their use of organic liquid electrolytes containing the iodide/tri-iodide redox couple, which causes serious problems such as electrode corrosion and electrolyte leakage 3 . Replacements for iodine-based liquid electrolytes have been extensively studied, but the efficiencies of the resulting devices remain low 3 , 4 , 5 , 6 , 7 , 8 , 9 . Here we show that the solution-processable p-type direct bandgap semiconductor CsSnI 3 can be used for hole conduction in lieu of a liquid electrolyte. The resulting solid-state dye-sensitized solar cells consist of CsSnI 2.95 F 0.05 doped with SnF 2 , nanoporous TiO 2 and the dye N719, and show conversion efficiencies of up to 10.2 per cent (8.51 per cent with a mask). With a bandgap of 1.3 electronvolts, CsSnI 3 enhances visible light absorption on the red side of the spectrum to outperform the typical dye-sensitized solar cells in this spectral region.

Power demands are set to increase by two-fold within the current century and a high fraction of that demand should be met by carbon free sources. Among the renewable energies, solar energy is among the fastest growing; therefore, a comprehensive and accurate design methodology for solar systems and how they interact with the local environment is vital. This paper addresses the environmental effects of solar panels on an unirrigated pasture that often experiences water stress. Changes to the microclimatology, soil moisture, water usage, and biomass productivity due to the presence of solar panels were quantified. The goal of this study was to show that the impacts of these factors should be considered in designing the solar farms to take advantage of potential net gains in agricultural and power production. Microclimatological stations were placed in the Rabbit Hills agrivoltaic solar arrays, located in Oregon State campus, two years after the solar array was installed. Soil moisture was quantified using neutron probe readings. Significant differences in mean air temperature, relative humidity, wind speed, wind direction, and soil moisture were observed. Areas under PV solar panels maintained higher soil moisture throughout the period of observation. A significant increase in late season biomass was also observed for areas under the PV panels (90% more biomass), and areas under PV panels were significantly more water efficient (328% more efficient).