Search Publications
Long-term changes in solar activity and irradiance
Chatzistergos, Theodosios; Krivova, Natalie A.; Yeo, Kok Leng
The Sun is the main energy source to Earth, and understanding its variability is of direct relevance to climate studies. Measurements of total solar irradiance (TSI) exist since 1978, but this is too short compared to climate-relevant time scales. Coming from a number of different instruments, these measurements require a cross-calibration, which …
Forecasting the transit times of earth-directed halo CMEs using artificial neural network: A case study application with GCS forward-modeling technique
Kozarev, K.; Minta, F. N.; Elsaid, A. +2 more
Mitigating the lethal threats caused by coronal mass ejections (CMEs) on human and space operations can be accomplished with a fast and accurate forecast of Earth-directed CME transit times. The current paper presents a robust Cascade Forward Neural Network (CFNN) framework to predict the transit times of Earth-directed halo CMEs using a total of …
Spacecraft radial alignments for investigations of the evolution of solar wind turbulence: A review
Telloni, Daniele
With the launch of the Parker Solar Probe, BepiColombo, and Solar Orbiter missions in the three-year period 2018 - 2020 , the investigation of the evolution of solar wind turbulence, dynamics, and structures in the inner heliosphere has become more readily feasible, thanks to the increasing availability of orbital configurations suitable for multi…
Lower-ionosphere electron density and effective recombination coefficients from multi-instrument space observations and ground VLF measurements during solar flares
Dominique, Marie; Žigman, Vida; Grubor, Davorka +2 more
A new model to predict the electron density and effective recombination coefficient of the lower ionosphere under solar flare conditions is presented. This model relies on space-borne solar irradiance measurements in coincidence with ground recorded active transmissions of Very Low Frequency (VLF), (<30 kHz) signals. Use is made of the irradian…
Solar active region magnetic parameters and their relationship with the properties of halo coronal mass ejections
Moon, Y. -J.; Shanmugaraju, A.; Ebenezer, E. +2 more
The coronal mass ejections (CMEs) from the sun consist of the plasma and strong magnetic fields (∼4-5 G at 1.3 R⊙) and generally, the fast CMEs are often associated with energetic particles of energy few hundreds of MeV. When the fast CMEs are ejected towards the Earth, they can disrupt the flow of solar wind in the heliosphere and impa…
Relating photometric and magnetic properties of structures at solar surface
Sokoloff, Dmitry; Obridko, Vladimir; Katsova, Maria
We investigate sharp structures visible in solar magnetic field tracers. It is shown that the sunspot magnetic boundaries do not coincide with the photometric ones. Moreover, there is no clear boundary of the magnetic field in the vicinity of sunspots. Thus, the widely accepted concept of magnetic tubes with sharp edges is not always correct and s…
Flapping motion configurations of geomagnetotail current sheet
Dunlop, M.; Rong, Zhaojin; Shen, Chao +5 more
We explore the geometry of the flapping motion of geomagnetotail current sheet with the magnetic measurements of the Cluster (constellation) using a newly developed technique. The principal curvatures and directions of the surfaces of the flapping current sheet are successfully deduced by the normal field analysis (NFA). Results show that the dire…