SEMINARS
SEMINARS - 2026
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Speaker: Dr. Paulo José de Aguiar Simões Affiliation: Mackenzie Presbyterian University Date/Time: June 9, 2026, at 2 PM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Precise timing of solar flare footpoint sources from mid-infrared observations Abstract: Solar flares are powerful particle accelerators, and in the accepted standard flare model, most of the flare energy is transported from a coronal energy-release region by accelerated electrons that stop collisionally in the chromosphere, heating and ionizing the plasma, producing a broad-band enhancement to the solar radiative output. We present a time-delay analysis of the infrared (IR) emission from two chromospheric sources in the flare SOL2014-09-24T17:50 taken at the McMath-Pierce telescope. By cross-correlating the intensity signals, measured with 1 s cadence, from the two spatially resolved IR sources we find a delay of 0.75 ± 0.07 s at 8.2 microns, where the uncertainties are quantified by a Monte Carlo analysis. The sources correlate well in brightness but have a time lag larger than can be reasonably explained by the energy transport dominated by non-thermal electrons precipitating from a single acceleration site in the corona. If interpreted as a time-of-flight difference between electrons traveling to each footpoint, we estimate time delays between 0.14 and 0.42 s, for a reconnection site at the interior quasi-separatrix layer, or at the null-point of the spine-fan topology inferred for this event. We employed modeling of electron transport via time-dependent Fokker-Planck and radiative hydrodynamic simulations to evaluate other possible sources of time-delay in the generation of the IR emission, such as differing ionization time-scales under different chromospheric conditions. Our results demonstrate that they are also unable to account for this discrepancy. This flare appears to require energy transport by some means other than electron beams originating in the corona. |
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Speaker: Dr. Luis Eduardo Antunes Vieira Affiliation: DIHPA/INPE Date/time: June 3, 2026, at 2:00 pm Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Reconstruction and Short-Term Forecast of Solar Total and Spectral Irradiance from Solar Magnetic Activity Abstract: Solar irradiance is the primary external energy source of the Earth system and a fundamental driver of the thermodynamic, chemical and electrodynamic state of the atmosphere. Variations of the total and spectral solar irradiance (TSI/SSI) on timescales from days to millennia are intimately linked to the evolution of solar magnetism, yet direct observations remain restricted to the spatial era and are affected by instrumental degradation, calibration uncertainties and incomplete spectral coverage. Physics-based reconstructions have demonstrated that the temporal evolution of the solar radiative output can be consistently inferred from the emergence, transport and decay of magnetic structures on the solar surface, while recent advances in machine learning and data assimilation have opened new possibilities for predictive irradiance modeling. Here we present a unified framework for the reconstruction and short-term forecast of the total and spectral solar irradiance by combining physics-based magnetic flux evolution models, solar surface observations and artificial intelligence techniques. The model assimilates full-disk magnetograms and continuum images to characterize the temporal evolution of active regions, faculae and the magnetic network, while recurrent neural architectures constrained by solar magnetic flux transport physics are employed to forecast irradiance variability from hours to days ahead. The framework reproduces irradiance variability over a broad spectral range, from the EUV to the infrared, and captures both rotational and solar-cycle signatures with wavelength-dependent accuracy. Our results demonstrate that the predictive capability strongly depends on the magnetic complexity and spatial distribution of solar active regions, with the highest forecast skill achieved in spectral bands dominated by magnetically driven chromospheric and coronal emission. The reconstruction further indicates that the long-term variability of irradiance is consistent with the secular evolution of the Sun’s magnetic flux since the Maunder Minimum and throughout the Holocene, reinforcing the central role of surface magnetism in modulating the solar radiative output. By extending irradiance modeling toward predictive operational capability, this work establishes a path toward next-generation space weather and climate services capable of providing near-real-time irradiance nowcasts and forecasts for ionospheric, thermospheric and climate applications. These results also highlight the importance of future solar missions dedicated to continuous multiwavelength observations of the solar magnetic field and radiative output, including out-of-ecliptic measurements required to constrain the anisotropy and global energetics of solar luminosity variability. |
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Speaker: MSc. Jayne Alencar de Melo Affiliation: Space Geophysics Postgraduate Program - PGGES/INPE Date/Time: May 20, 2026, at 2 PM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Space-ground coupling of ULF (Pc3-Pc5) waves in the South American sector Abstract: Ultra-low frequency (ULF) waves are fundamental drivers of energy transport within the coupled Magnetosphere-Ionosphere system. While the generation mechanisms for Pc5 (1.7-6.7 mHz) and Pc3 (22-100 mHz) pulsations are global, driven respectively by Kelvin-Helmholtz instabilities or internal resonances, and upstream ion-cyclotron waves, their transmission to the ground at low latitudes is significantly modified by regional electrodynamics. The South American sector acts as a unique natural laboratory for this coupling due to the South Atlantic Magnetic Anomaly (SAMA) and the Equatorial Electrojet (EEJ). This study presents an initial investigation into the Space-Ground coupling efficiency of ULF waves, testing the hypothesis that the South American ionosphere functions as an active electrodynamic filter. We employ a multi-point observation strategy combining in-situ magnetic field data from the Swarm constellation with ground-based magnetograms from the Embrace/INPE. Focusing on selected geomagnetic storm events, we analyze satellite passes traversing low-latitude L-shells (L < 2) over the South American sector. This configuration allows for a direct comparison between wave signatures observed at specific L-shells in space and the response at their corresponding magnetic footprints on the ground. This work aims to establish a framework for quantifying the active role of South American electrodynamics in modulating global magnetospheric energy transfer. |
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Speaker: Dr. Esfhan Alam Kherani Affiliation: National Institute for Space Research - INPE Date/Time: May 13, 2026, at 2 PM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Ionospheric Disturbances to Forecast Extreme Weather and Hazards Abstract: The ionosphere detects vibrations occurring near Earth’s surface and in the high-latitude middle atmosphere by hosting ionospheric vibrations or disturbances. This vertical and latitudinal coupling is highly energetic, involving atmospheric and plasma waves, such as acoustic-gravity waves and shear waves. The atmospheric waves have a unique property of amplifying the vibration near Earth’s surface by 1000 times at the ionospheric heights, so that even an undetectable vibration at the ground/troposphere can be detected in the ionosphere. This robust vertical coupling presents a promising scenario of forecasting extreme weather and hazards such as thunderstorms and earthquakes/tsunamis that often follow a series of weak vibrations near Earth’s surface. The present talk will focus on exploring the forecasting scenario of a few earthquakes and thunderstorms. |
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Speaker: Dr. Gustavo Andres Guerrero Eraso Affiliation: Federal University of Minas Gerais - UFMG Date/Time: May 7, 2026, at 2 PM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Computational Modeling of Solar Inertial Waves Abstract: One of the most relevant recent results in solar physics was the identification of global inertial modes through helioseismological observations. These modes include equatorial Rossby waves, high-latitude modes, and high-frequency modes. Such modes are highly sensitive to stellar structure, differential rotation, and the presence of magnetic fields. Therefore, these modes constitute natural probes of the solar internal dynamics. A rigorous theoretical interpretation can provide indirect, yet quantitative, observational links to the properties of the solar interior, including characteristics of the thermodynamic structure and/or the topology of the internal magnetic field, opening a new window for the study of problems previously inaccessible to direct observation. In this work, we initially describe solar inertial waves, then present a three-dimensional, non-linear computational model where we systematically explore the dependence of excited inertial modes on the model parameters. Our results allow a theoretical interpretation of the observations, providing information on different parameters of the solar interior. We found, for example, that high-latitude modes are a result of baroclinic instability, which in turn depends on radial shear in the tachocline. On the other hand, the excitation of Rossby-type equatorial modes depends on a permanent forcing mechanism. These modes are also highly sensitive to the amplitude and topology of the magnetic field, thus allowing the determination of possible internal magnetic configurations. |
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Speaker: Dr. Elisabete de Gouveia Dal Pino Affiliation: IAG-USP Date/Time: April 29, 2026, at 10:00 AM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Particle Acceleration by Turbulence-Driven Reconnection: From Space and Solar Plasmas to Astrophysical Systems. Abstract: Turbulence-driven magnetic reconnection is increasingly recognized as a fundamental mechanism for accelerating charged particles to high and very high energies in magnetized plasmas. It operates across a broad range of environments, from space and solar plasmas to extreme astrophysical systems associated with compact objects and extended magnetized flows. In this talk, I will present an overview of this acceleration process and a comparative analysis of particle energization in 3D magnetohydrodynamic (MHD) and particle-in-cell (PIC) simulations. I will examine how particle acceleration develops across both microscopic and macroscopic scales, drawing on results from 3D PIC kinetic simulations, hybrid 3D MHD-PIC models, and large-scale MHD simulations. While kinetic-scale PIC models are essential for addressing the injection problem—the initial stage of particle acceleration—macroscopic MHD simulations are needed to determine how particles continue to gain energy and what maximum energies can be reached. I will highlight the main similarities and differences between these regimes, their impact on acceleration rates and energy spectra, and how the transition from micro to macro scales shapes the overall acceleration process. I will further show that particle acceleration in 3D turbulent reconnection is primarily governed by a Fermi-type process, rather than by drift acceleration. This mechanism provides an efficient route to particle energization over a wide range of plasma conditions, with important implications not only for astrophysical sources but also for space and solar plasma environments. Although the main examples will focus on astrophysical systems, particularly active galactic nuclei (AGN), the underlying physical process is quite general and directly relevant to the broader plasma community. I will conclude by discussing applications to AGN sources. |
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Speaker: MSc. Roberto Livy da Costa Madeira Affiliation: Space Geophysics Postgraduate Program - PGGES/INPE Date/time: April 23, 2026, at 2pm Location: Roger Honiat Auditorium (LIT building) Title: On the relations between spectral and temporal parameters of the ionospheric scintillation phenomenon observed by a stand-alone GNSS receiver at Cachoeira Paulista in Brazil. Abstract: Among the topics of greatest interest in aeronomy today, equatorial ionospheric scintillation of the GNSS (global navigation satellite system) signals stands out. It is defined as the rapid variation of amplitude and phase of the signals that crossed the disturbed low latitudinal ionosphere. The observed phenomenon, by receivers, depends on the characteristic scale length of the irregularities that develop within the equatorial plasma bubbles under a cascade process. In this work, we collect intensity data from a geostationary satellite at 5°W and present empirical evidence supporting the possibility of probing and modeling properties of ionospheric irregularities over Brazil using a stand-alone receiver in Cachoeira Paulista. In particular, we show that, under the frozen-in hypothesis, the characteristic frequency of the intensity scintillation spectrum is inversely proportional to the decorrelation time, which, in turn, is inversely proportional to the drift velocity. |
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Speaker: Dr. Erico L. Rempel Affiliation: Department of Mathematics, ITA and DGE/INPE Date: April 15, 2026, at 2 PM Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: LAGRANGIAN COHERENT STRUCTURES IN SPACE PLASMAS Abstract: Space plasmas can be described as turbulent conductive flows, where the fluid motion is determined by a series of coherent kinetic and magnetic structures of different types. Identifying and monitoring the evolution of these structures is crucial for a deep understanding and, possibly, for predicting plasma behavior. Lagrangian coherent structures constitute a recently developed theory to describe the transport of materials in fluids, with carefully crafted mathematical approaches to detect the main transport barriers responsible for controlling fluid flows. In this work, we review the application of this theory to space plasmas using numerical simulations and satellite observations. In particular, the results show that Lagrangian coherent structures can be used to better understand complex plasma phenomena in the solar atmosphere. |
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Speaker: Dr. Diego Janches Affiliation: NASA Goddard Space Flight Center, Greenbelt, United States Date: April 14, 2026, at 2pm Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Global Network of Meteor Radars: A Critical Atmospheric Capability for Space Weather Operations Abstract: This talk highlights the importance of a global network of meteor radars as a key observational system for monitoring the upper atmosphere. It discusses how these measurements are obtained and provides critical data on winds, and variability that directly impacts spatial weather operations. The presentation emphasizes the role of coordinated international observations in improving forecasting capabilities and supporting both scientific research and operational needs. |
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Speaker: Prof. Dr. Walmir Thomazzi Cardoso (UFRJ) Date: April 8, 2026 Location: Barclay Clemesha Auditorium, CEA II building, INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Seminar Title: We are under many skies: Cultural Astronomy as a field of academic research. Abstract: Where we see a scorpion in the sky, the Tukano indigenous people of the Upper Rio Negro see a jararaca snake, and some Guarani villages see part of the body of a rhea. Beyond distinct arrangements and designs in the sky, these representations reveal part of the complex relationships existing in each culture, including their conceptions of the natural world. In times of global climate change, what can we learn from the sky-earth relationships locally established by human groups? |
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Speaker: Jean Carlo Santos Affiliation: National Institute for Space Research (INPE) Date: April 01, 2026, at 2pm Location: Barclay Clemesha Auditorium, CEA II building, at INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja)
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Speaker: Dr. Ramon E. Lopez Distinguished Researcher and Professor Member, U.T. System & U.T. Arlington Academy of Distinguished Teachers Department of Physics, University of Texas at Arlington Date/Time: March 26, 2:00 PM Location: Barclay Clemesha Auditorium, CEA II building, INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: Magnetospheres and the possibility of life on other planets. Language: English |
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Speaker: Walter D. Gonzalez Affiliation: National Institute for Space Research (INPE) Date: March 11, 2026 at 10am Location: Barclay Clemesha Auditorium, CEA II building, INPE headquarters in São José dos Campos (Av. dos Astronautas, 1758, Jardim da Granja) Title: SMILE Mission Abstract: The SMILE (Solar Wind - Magnetosphere - Ionosphere Link Explorer) mission, from ESA (European Space Agency) and CAS (Chinese Academy of Sciences), expected to launch in April 2026 (and be placed in an elliptical orbit with an apogee of 30 Earth radii and inclined relative to the ecliptic), aims to monitor fundamental aspects of the interaction of the solar wind with the Earth's magnetosphere, using sensors to measure plasma and interplanetary magnetic field, X-ray emission from the magnetosheath and the The study will explore the magnetopause, as well as UV emission from the auroral region. These measurements are expected to provide a better understanding of global aspects of the magnetopause and the auroral region, particularly during periods of intense geomagnetic storms and sub-storms.
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