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The Planetary Theory of Solar Activity Variability: A Review
Scafetta, Nicola; Bianchini, Antonio
Commenting the 11-year sunspot cycle, Wolf (1859, MNRAS 19, 85–86) conjectured that "the variations of spot-frequency depend on the influences of Venus, Earth, Jupiter, and Saturn." The high synchronization of our planetary system is already nicely revealed by the fact that the ratios of the planetary orbital radii are closely related to each othe…
Solar Jets: SDO and IRIS Observations in the Perspective of New MHD Simulations
Schmieder, Brigitte
Solar jets are observed as collimated plasma beams over a large range of temperatures and wavelengths. They have been observed in H α and optical lines for more than 50 years and called surges. The term "jet" comes from X-ray observations after the launch of the Yohkoh satellite in 1991. They are the means of transporting energy through the helios…
Eruption and Interplanetary Evolution of a Stealthy Streamer-Blowout CME Observed by PSP at ∼0.5 AU
Lynch, Benjamin J.; Palmerio, Erika; Stevens, Michael L. +5 more
Streamer-blowout coronal mass ejections (SBO-CMEs) are the dominant CME population during solar minimum. Although they are typically slow and lack clear low-coronal signatures, they can cause geomagnetic storms. With the aid of extrapolated coronal fields and remote observations of the off-limb low corona, we study the initiation of an SBO-CME pre…
Predicting CME arrival time through data integration and ensemble learning
Xu, Yan; Jing, Ju; Wang, Haimin +7 more
The Sun constantly releases radiation and plasma into the heliosphere. Sporadically, the Sun launches solar eruptions such as flares and coronal mass ejections (CMEs). CMEs carry away a huge amount of mass and magnetic flux with them. An Earth-directed CME can cause serious consequences to the human system. It can destroy power grids/pipelines, sa…
Primary and albedo protons detected by the Lunar Lander Neutron and Dosimetry experiment on the lunar farside
Xu, Zigong; Guo, Jingnan; Wimmer-Schweingruber, Robert F. +4 more
The Lunar Lander Neutron and Dosimetry (LND) Experiment aboard the Chang'E-4 Lander on the lunar far-side measures energetic charged and neutral particles and monitors the corresponding radiation levels. During solar quiet times, galactic cosmic rays (GCRs) are the dominating component of charged particles on the lunar surface. Moreover, the inter…
A Multi-Event Study of Early-Stage SEP Acceleration by CME-Driven Shocks—Sun to 1 AU
Zucca, Pietro; Kozarev, Kamen; Nedal, Mohamed +2 more
The solar corona between below 10 solar radii is an important region for early acceleration and transport of solar energetic particles (SEPs) by coronal mass ejection-driven shock waves. There, these waves propagate into a highly variable dynamic medium with steep gradients and rapidly expanding coronal magnetic fields, which modulates the particl…
Uniting the Sun's Hale magnetic cycle and "extended solar cycle" paradigms
McIntosh, Scott W.; Leamon, Robert J.; Scherrer, Philip H. +1 more
Through meticulous daily observation of the Sun's large-scale magnetic field the Wilcox Solar Observatory (WSO) has catalogued two magnetic (Hale) cycles of solar activity. Those two (∼22-year long) Hale cycles have yielded four (∼11-year long) sunspot cycles (numbers 21 through 24). Recent research has highlighted the persistence of the "Extended…
Effect of an Interplanetary Coronal Mass Ejection on Saturn's Radio Emission
Jackman, C. M.; Cecconi, B.; Sánchez-Cano, B. +2 more
The Saturn Kilometric Radiation (SKR) was observed for the first time during the flyby of Saturn by the Voyager spacecraft in 1980. These radio emissions, in the range of a few kHz to 1 MHz, are emitted by electrons travelling around auroral magnetic field lines. Their study is useful to understand the variability of a magnetosphere and its coupli…
Quaternionic Transform: A new Light on the Solar Power Spectrum
Garrido, Rafael; Ayala, Adrián; Pascual-Granado, Javier +2 more
Asteroseismology, that is, the use of the frequency content of a time series caused by variations in brightness or radial velocity of a stellar object, is based on the hypothesis that such a series is harmonic and therefore can be described by a sum of sines and cosines. If this were not the case (e.g., the oscillations of an ellipsoid of revoluti…