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Upflows in the Upper Solar Atmosphere
Tian, Hui; Brooks, David H.; Baker, Deborah +2 more
Spectroscopic observations at extreme- and far-ultraviolet wavelengths have revealed systematic upflows in the solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of active regions, and dimming regions associated with coronal mass ejections. They have been intensi…
Probabilistic Drag-Based Ensemble Model (DBEM) Evaluation for Heliospheric Propagation of CMEs
Veronig, Astrid M.; Dumbović, Mateja; Temmer, Manuela +4 more
The Drag-based Model (DBM) is a 2D analytical model for heliospheric propagation of Coronal Mass Ejections (CMEs) in ecliptic plane predicting the CME arrival time and speed at Earth or any other given target in the solar system. It is based on the equation of motion and depends on initial CME parameters, background solar wind speed, w and the dra…
Assessing the Predictability of Solar Energetic Particles with the Use of Machine Learning Techniques
Lavasa, E.; Giannopoulos, G.; Papaioannou, A. +5 more
A consistent approach for the inherently imbalanced problem of solar energetic particle (SEP) events binary prediction is being presented. This is based on solar flare and coronal mass ejection (CME) data and combinations of both thereof. We exploit several machine learning (ML) and conventional statistics techniques to predict SEPs. The methods u…
Role of Compressive Viscosity and Thermal Conductivity on the Damping of Slow Waves in Coronal Loops with and Without Heating-Cooling Imbalance
Srivastava, A. K.; Wang, T. J.; Prasad, Abhinav
In the present article, we derive a new dispersion relation for slow magnetoacoustic waves invoking the effect of thermal conductivity, compressive viscosity, radiation, and an unknown heating term along with the consideration of heating-cooling imbalance from linearized MHD equations. We solve the general dispersion relation to understand the rol…
Measurements of Solar Differential Rotation Using the Century Long Kodaikanal Sunspot Data
Chatterjee, Subhamoy; Banerjee, Dipankar; Jha, Bibhuti Kumar +2 more
The rotational profile of the Sun is considered to be one of the key inputs in a solar dynamo model. Hence, precise and long-term measurements of this quantity is important for our understanding of solar magnetism and its variability. In this study, we use the newly digitised, white-light sunspot data (1923 - 2011) from Kodaikanal Solar Observator…
CME-Driven and Flare-Ignited Fast Magnetosonic Waves Detected in a Solar Eruption
Shen, Yuandeng; Zhou, Chengrui; Zhou, Xinping +4 more
We present Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observation of three types of fast-mode, propagating, magnetosonic waves in a GOES C3.0 flare on 23 April 2013, which was accompanied by a prominence eruption and a broad coronal mass ejection (CME). During the fast-rising phase of the prominence, a large-scale, dome-shap…
Science Highlights and Final Updates from 17 Years of Total Solar Irradiance Measurements from the SOlar Radiation and Climate Experiment/Total Irradiance Monitor (SORCE/TIM)
Kopp, Greg
The final version (V.19) of the total solar irradiance data from the SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor has been released. This version includes all calibrations updated to the end of the mission and provides irradiance data from 25 February 2003 through 25 February 2020. These final calibrations are presented …
Empirical Model of 10 - 130 MeV Solar Energetic Particle Spectra at 1 AU Based on Coronal Mass Ejection Speed and Direction
Richardson, Ian G.; Bruno, Alessandro
We present a new empirical model to predict solar energetic particle (SEP) event-integrated and peak intensity spectra between 10 and 130 MeV at 1 AU, based on multi-point spacecraft measurements from the Solar TErrestrial RElations Observatory (STEREO), the Geostationary Operational Environmental Satellites (GOES), and the Payload for Antimatter …
Propagating Conditions and the Time of ICME Arrival: A Comparison of the Effective Acceleration Model with ENLIL and DBEM Models
Vourlidas, Angelos; Dumbović, Mateja; Papaioannou, Athanasios +5 more
The Effective Acceleration Model (EAM) predicts the Time-of-Arrival (ToA) of the Coronal Mass Ejection (CME) driven shock and the average speed within the sheath at 1 AU. The model is based on the assumption that the ambient solar wind interacts with the interplanetary CME (ICME) resulting in constant acceleration or deceleration. The upgraded ver…
Deciphering Solar Magnetic Activity: 140 Years of the `Extended Solar Cycle' - Mapping the Hale Cycle
Velli, Marco; McIntosh, Scott W.; Srivastava, Abhishek K. +6 more
We investigate the occurrence of the "extended solar cycle" (ESC) as it occurs in a host of observational data spanning 140 years. Investigating coronal, chromospheric, photospheric, and interior diagnostics, we develop a consistent picture of solar activity migration linked to the 22-year Hale (magnetic) cycle using superposed epoch analysis (SEA…