Efficient heat transfer of concentrated solar energy and rapid chemical kinetics are desired characteristics of solar thermochemical redox cycles for splitting CO2. We have fabricated reticulated porous ceramic (foam-type) structures made of ceria with dual-scale porosity in the millimeter and micrometer ranges. The larger void size range, with dmean = 2.5 mm and porosity = 0.76-0.82, enables v...

We present a detailed study of variations observed in low-angular degree solar p-mode frequencies during solar cycles 22 and 23, and their relation to global and spatially decomposed proxies of the surface activity. To do so, we have analysed 11 yr of unresolved (Sun-as-a-star) Doppler velocity observations of the solar disc made by the Birmingham Solar-Oscillations Network (BiSON). The sensiti...

We investigated geomagnetic activity which was induced by interplanetary magnetic clouds during the past four solar cycles, 1965–1998. We have found that the intensity of such geomagnetic storms is more severe in solar maximum than in solar minimum. In addition, we affirm that the average solar wind speed of magnetic clouds is faster in solar maximum than in solar minimum. In this study, we fin...

Total solar irradiance reconstructed between 1978 and 2003 using solar surface magnetic field distributions is compared with three composites of total solar irradiance measurements. A good correspondence is found with the total solar irradiance composite from PMOD/WRC, with no bias between the three cycles. The agreement with the other composites (the ACRIM composite, mainly based on the Active...

HO2 and OH, also known as HOx, play an important role in controlling middle atmospheric O3. Due to their photochemical production and short chemical lifetimes, HOx are expected to respond rapidly to solar irradiance changes, resulting in O3 variability. While OH solar cycle signals have been investigated, HO2 studies have been limited by the lack of reliable observations. Here we present the fi...

The solar polar fields reverse because magnetic flux from decaying sunspots moves towards the poles, with a preponderance of flux from the trailing spots. If there is a strong asymmetry in the sense that most activity is in the Northern Hemisphere, then that excess flux will move to the North Pole and reverse that pole first. If later on, there is more activity in the South, then that flux will...

The interstellar cloud surrounding the solar system regulates the galactic environment of the Sun and constrains the physical characteristics of the interplanetary medium. This paper compares interstellar dust grain properties observed within the solar system with dust properties inferred from observations of the cloud surrounding the solar system. Properties of diffuse clouds in the solar vici...

The interstellar cloud surrounding the solar system regulates the galactic environment of the Sun and constrains the physical characteristics of the interplanetary medium. This paper compares interstellar dust grain properties observed within the solar system with dust properties inferred from observations of the cloud surrounding the solar system. Properties of diffuse clouds in the solar vici...

New observations of low energy (--1 to 200 MeV/nuc) cosmic rays measured by three newly launched experiments on SAMPEX during 1992 and 1993 show the strong presence of anomalous cosmic ray (ACR) nitrogen and oxygen, well before the approaching solar minimum. When compared with ACR temporal variations over the past two solar cycles we find that the 1992-1993 fluxes are -5 to 10 times their level...