Publications by Antonio Sunjerga

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Lightning physics is highly multidisciplinary, involving areas such as plasma physics, electrical engineering, meteorology, thermodynamics and particle physics. Upward lightning is a special type of lightning initiated from tall structures that has attract ...

Far-field measurements of lightning-produced electromagnetic fields are of high importance for lightning location systems. Data from recorded lightning strokes can be, for example, used to assess the risk of lightning-induced damage in some geographical ar ...

Tall structures such as wind turbines and mobile phone base stations are often installed in remote and hilly locations to gain more power or to have line of sight to end users. Those locations are usually very rocky and characterized by a low-conductivity ...

Meteorological conditions favoring the initiation of upward lightning from tall structures have been only poorly investigated so far. In addition to the scientific interest in this subject, it has practical applications to risk assessment for lightning occ ...

We present an analysis aimed at evaluating the effect of the presence of the tower on the measurement of the grounding impedance. The Numerical Electromagnetics Code NEC-4 is used for the full-wave modeling of the structure including the tower and its foot ...

X-rays have been observed in natural downward cloud-to-ground lightning for over 20 years and in rocket-triggered lightning for slightly less. In both cases, this energetic radiation has been detected during the stepped and dart leader phases of downward n ...

The lightning discharge current is characterized by a high-frequency spectrum extending from DC to about 10 MHz. The calculation of the grounding impedance is one of the most important aspects of designing lightning protection systems. The search for analy ...

The electrodynamics of the Terrestrial Gamma Ray Flash (TGF) are not fully understood but the last decade has seen compelling observations in lightning leader (+IC) radio emission that have linked a subset of TGF satellite observations with unique waveform ...

Lightning is one of the main causes of damage to wind turbines. The continuous increase in the wind turbine heights makes these structures even more vulnerable against lightning. As a result, the design of proper lightning protection system is of high impo ...

Interest in exploring the meteorological conditions favoring upward lightning from tall man-made structures has grown in recent years, largely due to the worldwide expansion of wind energy. To this end, instrumented towers existing around the world are the ...

In this paper, we analyze the grounding resistance of a vertical grounding rod located in an elevated terrain. Tall structures such as wind turbines and mobile phone base stations are often installed in remote and hilly locations to gain more power or to f ...

Lightning discharges between charged clouds and the Earth’s surface are responsible for considerable damages and casualties. It is therefore important to develop better protection methods in addition to the traditional Franklin rod. Here we present the fir ...

Controlling lightning is a long-time dream of mankind. Along with the rapid evolution of laser technologies, the idea to develop lightning protection based on filamentation of high-power ultrashort-pulse lasers emerged in the 1990s [1]. The goal of the Las ...

We present an analysis of the response of a grounding electrode located on the top of a mountain. Specifically, we derive an analytical solution for the low-frequency response of a hemispheric grounding electrode buried on the top of a cone-shaped mountain ...

Lightning is highly destructive due to its high power density and unpredictable character. Directing lightning away would allow to protect sensitive sites from its direct and indirect impacts (electromagnetic perturbations). Up to now, lasers have been una ...

The Säntis Tower was instrumented in May 2010 to measure currents of lightning discharges striking the tower. Since then the system has been recurrently updated and expanded. Currently, data associated with lightning strikes to the tower are collected at f ...

We report the observation of three negative upward flashes recorded by a high-speed camera at the Säntis Tower during the Summer of 2019. The camera was operating at 10,000 fps and an exposure time of 99 μs. Simultaneous measurements of the lightning curre ...

Wind turbines are very vulnerable to lightning because of their height, sharp edges and remote locations often with low soil conductivity. In this paper we present numerical simulations of the impedance of a typical wind turbine grounding geometry. We anal ...

Wind turbines are very vulnerable to lightning strikes due to their height, sharp edges and remote locations often with high soil resistivity. In this paper we present numerical simulations of the impedance of a typical wind turbine grounding geometry. We ...

We report on the mountain top observation of three terrestrial gamma-ray flashes (TGFs) that occurred during the summer storm season of 2021. To our knowledge, these are the first TGFs observed in a mountaintop environment and the first published European ...

Antonio Sunjerga

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Lightning to tall structures: Characterization, Modeling and Protection

Multiple-Station Measurements of a Return-Stroke Electric Field From Rocket-Triggered Lightning at Distances of 68-126 km

Reduction of a Cone-Shaped Terrain Grounding Resistance by Remote Grounding

Meteorological conditions during self-initiated upward lightning at the Säntis tower (Switzerland)

Tower and Path-Dependent Voltage Effects on the Measurement of Grounding Impedance for Lightning Studies

Direct observations of X-rays produced by upward positive lightning

High-frequency response of a hemispherical grounding electrode

Mountaintop gamma ray observations of two TGFs at the Santis Tower, Switzerland with coincident radio waveforms characteristic of a RREA current pulse

On Wind Turbine Impedance Analysis via Different Approaches

Meteorological Aspects of Self-Initiated Upward Lightning at the Santis Tower (Switzerland)

On the Influence of an Elevated Terrain on the Grounding Resistance of a Vertical Rod

Laser-guided lightning

Laser-guided lightning using kHz filamentation at 1030 nm

Calculation of the Grounding Resistance of Structures Located on Elevated Terrain

The laser lightning rod project

Säntis Lightning Research Facility Instrumentation

Bidirectional Recoil Leaders in Upward Lightning Flashes Observed at the Säntis Tower

Transient Impedance of Interconnected Wind Turbine Grounding Systems

Isolated vs. Interconnected Wind Turbine Grounding Systems: Effect on the Harmonic Grounding Impedance, Ground Potential Rise and Step Voltage

Mountaintop Gamma Ray Observations of Three Terrestrial Gamma‐Ray Flashes at the Säntis Tower, Switzerland With Coincident Radio Waveforms