Earth Connection Research Articles

SMILE Winter Campaign

ABSTRACT This white paper is highly topical as it relates to the upcoming solar wind magnetosphere ionosphere link explorer (SMILE) mission: SMILE is a joint mission between the European Space Agency and the Chinese Academy of Sciences and it aims to build a more complete understanding of the Sun–Earth connection by measuring the solar wind and its dynamic interaction with the magnetosphere. It is a fully funded mission with a projected launch in 2025. This paper outlines a plan for action for SMILE’s first Northern hemisphere winter campaign using ground-based instruments. We outline open questions and which data and techniques can be employed to answer them. The science themes we discuss are: (i) Earth’s magnetosheath, magnetopause, and magnetic cusp impact on the ionospheric cusp region; (ii) defining the relationship between auroral processes, solar wind, and magnetospheric drivers; (iii) understanding the interhemispheric properties of the Earth’s magnetosphere–ionosphere system. We discuss open questions (different to the mission goals) which may be answered using existing ground-based instrumentation together with SMILE data to leverage the maximum scientific return of the mission during the first winter after launch. This paper acts as a resource for planning, and a call to collaborative action for the scientific community.

Fully numerical computation of heteroclinic connection families in the spatial three-body problem

Heteroclinic connections in the spatial circular restricted three-body problem play an important role in astrodynamics. This paper presents a fully numerical methodology for the computation of the two-parameter families of connections that exist between families of invariant tori in the three-body problem. The computation of connections is presented as a two-point boundary value problem in which the initial and final states belong to unstable and stable manifolds of two respective normally hyperbolic invariant manifolds. A flow map torus computation procedure is modified to compute particular trajectories within these spaces, and a robust two-parameter continuation scheme is paired with a shooting technique to compute the entire connection family. Results are provided in the Sun–Earth and Earth–Moon representations of the spatial three-body problem. The Sun–Earth connection family works to verify the methodology with previously developed semi-analytical connection computation techniques. The Earth–Moon example demonstrates the methodology in a setting where fully numerical techniques are required to study the connection family.

A Hale-like Cycle in the Solar Twin 18 Scorpii

Abstract Characterizing the cyclic magnetic activity of stars that are close approximations of our Sun offers our best hope for understanding our Sun’s current and past magnetism, the space weather around solar-type stars, and more generally, the dynamos of other cool stars. The nearest current approximation to the Sun is the solar twin 18 Scorpii, a naked-eye Sun-like star of spectral type G2 Va. However, while 18 Scorpii’s physical parameters closely match those of the Sun, its activity cycle is about 7 yr, and shorter than the solar cycle. We report the measurement of a periodicity of 15 yr that corresponds to a longer activity cycle for 18 Scorpii based on observations extending to the last three decades. The global magnetic geometry of 18 Scorpii changes with this 15 yr cycle and appears to be equivalent to the solar 22 yr magnetic polarity cycle. These results suggest that 18 Scorpii is also a magnetic proxy for a younger Sun, adding an important new datum for testing dynamo theory and magnetic evolution of low-mass stars. The results perturb our understanding of the relationship between cycle and rotation, constrain the Sun’s magnetism and the Sun–Earth connection over the past billion years, and suggest that solar Schwabe and Hale cycle periods have increased over that time span.

Near-Sun In Situ and Remote-sensing Observations of a Coronal Mass Ejection and its Effect on the Heliospheric Current Sheet

During the thirteenth encounter of the Parker Solar Probe (PSP) mission, the spacecraft traveled through a topologically complex interplanetary coronal mass ejection (ICME) beginning on 2022 September 5. PSP traversed through the flank and wake of the ICME while observing the event for nearly two days. The Solar Probe ANalyzer and FIELDS instruments collected in situ measurements of the plasma particles and magnetic field at ∼13.3 R S from the Sun. We observe classical ICME signatures, such as a fast-forward shock, bidirectional electrons, low proton temperatures, low plasma β, and high alpha particle to proton number density ratios. In addition, PSP traveled through two magnetic inversion lines, a magnetic reconnection exhaust, and multiple sub-Alfvénic regions. We compare these in situ measurements to remote-sensing observations from the Wide-field Imager for Solar PRobe Plus instrument on board PSP and the Sun Earth Connection Coronal and Heliospheric Investigation on the Solar Terrestrial Relations Observatory. Based on white-light coronagraphs, two CMEs are forward modeled to best fit the extent of the event. Furthermore, Air Force Data Assimilative Flux Transport magnetograms modeled from Global Oscillation Network Group magnetograms and Potential Field Source Surface modeling portray a global reconfiguration of the heliospheric current sheet (HCS) after the CME event, suggesting that these eruptions play a significant role in the evolution of the HCS.

A Practical Study of "Cloud Earth Connection" for Blended Teaching of College English Reading

This paper presents a comprehensive exploration of the innovative teaching methodology known as the "Cloud Earth Connection" in the context of college English reading instruction. Grounded in the principles of blended teaching, this practical study delves into the seamless integration of cloud technology with traditional pedagogy, fostering a dynamic and interactive learning environment. Through a rigorous examination of this approach, the paper investigates its pedagogical implications, effectiveness, and impact on student engagement and learning outcomes. Drawing on empirical research and theoretical frameworks, the study assesses the practical applications and challenges of the "Cloud Earth Connection" method, offering valuable insights into its potential to enhance college English reading education. This research contributes to the growing body of knowledge on blended teaching strategies and provides practical guidance for educators seeking innovative and effective ways to engage students in the digital age.

Development of a Lightning Prediction Model Using Machine Learning Algorithm: Survey.

This research is aimed at preventing broadcast equipment from lightning damage. Inview of the location in which my broadcast outfit is located (located in a valley; some few meters above sea level in the Confluence of Lokoja Kogi State Nigeria). Several improvement of earthing and installation of lightning arresting facilities, there has not been significant change protecting broadcast equipment from lightning. The solution I proffered is to isolate all electrical connection from equipment. Lightning as a natural phenomenon is very unpredictive and destructive which can occur during transmission. How do we know the day and time distructive lightning will come? The answer is to develop a lightning prediction system that is accurate. When lightning lead time is known, personnel on duty will be alerted to isolate all broadcast equipment from the mains and central earth connection. Since the lightning prediction system has to be localized. Deployment of machine learning algorithm is most appropriate. The use of ten(10) years Weather Numerical Values(2012-2022) such as rainfall, atmospheric pressure, relative humidity, temperature and lightning records which are gotten from Nigeria Meteorological Agency (NIMET), Lokoja Area Office, Kogi State. This parametization are factors that are used to work on the lightning forecast system as lightning will occur at their certain threshold values. The model is intended to be deployed on web application. Prediction model can be localized to support Numerical Weather Prediction in any environment in Nigeria.

Considering humans as integral components of “nature”

Considering humans as integral components of “nature”

Multi-Spacecraft Observations of an Interplanetary Coronal Mass Ejection Interacting with Two Solar-Wind Regimes Observed by the Ulysses and Twin-STEREO Spacecraft

We present a combined study of a coronal mass ejection (CME), revealed in a unique orbital configuration that permits the analysis of remote-sensing observations on 27 June 2007 from the twin Solar Terrestrial Relations Observatory (STEREO)-A and -B spacecraft and of its subsequent in situ counterpart outside the ecliptic plane, the interplanetary coronal mass ejection (ICME) observed on 04 July 2007 by Ulysses at 1.5 AU and heliographic-Earth-ecliptic coordinates system (HEE) 33° latitude and 49° longitude. We apply a triangulation method to the STEREO Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) COR2 coronagraph images of the CME, and a self-similar expansion fitting method to STEREO/SECCHI Heliospheric Imager (HI)-B. At Ulysses we observe: a preceding forward shock, followed by a sheath region, a magnetic cloud, a rear forward shock, followed by a compression region due to a succeeding high-speed stream (HSS) interacting with the ICME. From a minimum variance analysis (MVA) and a length-scale analysis we infer that the magnetic cloud at Ulysses, with a duration of 24 h, has a west-north-east configuration, length scale of ≈0.2 AU, and mean expansion speed of 14.2 km s−1. The relatively small size of this ICME is likely to be a result of its interaction with the succeeding HSS. This ICME differs from the previously known over-expanding types observed by Ulysses, in that it straddles a region between the slow and fast solar wind that in itself drives the rear shock. We describe the agreements and limitations of these observations in comparison with 3D magneto-hydrodynamic (MHD) heliospheric simulations of the ICME in the context of a complex solar-wind environment.

Lightning Performance of Multiple Horizontal, Vertical and Inclined Grounding Electrodes

Single horizontal and vertical grounding electrodes are often used for an earth connection of the lightning protection system. However, there are many practical situations when such electrodes have to be enhanced for better efficiency and replaced by multiple horizontal, vertical and/or inclined electrodes. This paper presents a systematic approach to evaluating and comparing the lightning performance of such grounding arrangements based on simple formulas. The contributions of this paper are: It is shown that impulse impedance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> may be derived from known formulas for low-frequency grounding resistance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> ; a new definition of effective length is introduced that allows for such a derivation; a collection of accurate formulas for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> of all considered grounding electrode arrangements is presented; and a new concept of “effective volume” is described that enables a simple procedure to increase electrodes’ effective length. The new formulas for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> , and effective length of the different electrode arrangements allow an analysis that might help search for a choice of cost-effective configuration and dimensions of the grounding systems in the early design stage.

Three-dimensional analyses of an aspherical coronal mass ejection and its driven shock

Context. Observations reveal that shocks can be driven by fast coronal mass ejections (CMEs) and play essential roles in particle accelerations. A critical ratio, δ, derived from a shock standoff distance normalized by the radius of curvature (ROC) of a CME, allows us to estimate shock and ambient coronal parameters. However, true ROCs of CMEs are difficult to measure due to observed projection effects. Aims. We investigate the formation mechanism of a shock driven by an aspherical CME without evident lateral expansion. Through three-dimensional (3D) reconstructions without a priori assumptions of the object morphology, we estimate the two principal ROCs of the CME surface and demonstrate how the difference between the two principal ROCs of the CME affects the estimate of the coronal physical parameters. Methods. The CME was observed by the Sun Earth Connection Coronal and Heliospheric Investigation instruments and the Large Angle and Spectrometric Coronagraph. We used the mask-fitting method to obtain the irregular 3D shape of the CME and reconstructed the shock surface using the bow-shock model. Through smoothings with fifth-order polynomial functions and Monte Carlo simulations, we calculated the ROCs at the CME nose. Results. We find that (1) the maximal ROC is two to four times the minimal ROC of the CME. A significant difference between the CME ROCs implies that the assumption of one ROC of an aspherical CME could cause overestimations or underestimations of the shock and coronal parameters. (2) The shock nose obeys the bow-shock formation mechanism, considering the constant standoff distance and the similar speed between the shock and CME around the nose. (3) With a more precise δ calculated via 3D ROCs in space, we derive corona parameters at high latitudes of about −50°, including the Alfvén speed and the coronal magnetic field strength.

A New Standalone Tool for DC‐Equivalent Network Generation and GIC Calculation in Power Grids With Multiple Voltage Levels

AbstractSpace Weather phenomena pose a major socio‐economic threat due, in part, to the vulnerability of power network transformers to geomagnetically induced currents (GIC). In 1985, Lehtinen and Pirjola (LP) provided a method to calculate GICs in a single‐voltage‐level network. The need to account for lower voltages has caused the proliferation of GIC risk assessments applied to power grids with multiple voltages. We hereby present a tool to systematically generate the direct currents (DC)‐equivalent of a multiple‐voltage‐level network. The LP and Nodal Admittance Matrix methods are the most popular schemes to compute the GIC from the resulting equivalent network by solving the circuit laws for the earthing current or the voltage at each node, respectively. A new scheme is presented here that solves the circuit laws for the current flowing between the bus nodes and the neutral point which, unlike LP, requires no (infinite‐resistance) earth connections for the buses. The number of equations/unknowns of the resulting GIC matrix equation is reduced compared to the traditional methods, thus optimizing the computational cost ‐an advantage that becomes important for large networks‐, while keeping a good condition of the design matrix associated with the inversion. Examples are shown for different test cases and a standalone computationally efficient code is provided.

Acceleration of Solar Energetic Particles through CME-driven Shock and Streamer Interaction

Abstract On 2013 June 21, a solar prominence eruption was observed, accompanied by an M2.9 class flare, a fast coronal mass ejection, and a type II radio burst. The concomitant emission of solar energetic particles (SEPs) produced a significant proton flux increase, in the energy range 4–100 MeV, measured by the Low and High Energy Telescopes on board the Solar TErrestrial RElations Observatory (STEREO)-B spacecraft. Only small enhancements, at lower energies, were observed at the STEREO-A and Geostationary Operational Environmental Satellite (GOES) spacecraft. This work investigates the relationship between the expanding front, coronal streamers, and the SEP fluxes observed at different locations. Extreme-ultraviolet data, acquired by the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO), were used to study the expanding front and its interaction with streamer structures in the low corona. The 3D shape of the expanding front was reconstructed and extrapolated at different times by using SDO/AIA, STEREO/Sun Earth Connection Coronal and Heliospheric Investigation, and Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph observations with a spheroidal model. By adopting a potential field source surface approximation and estimating the magnetic connection of the Parker spiral, below and above 2.5 R ⊙, we found that during the early expansion of the eruption, the front had a strong magnetic connection with STEREO-B (between the nose and flank of the eruption front) while having a weak connection with STEREO-A and GOES. The obtained results provide evidence, for the first time, that the interaction between an expanding front and streamer structures can be responsible for the acceleration of high-energy SEPs up to at least 100 MeV, as it favors particle trapping and hence increases the shock acceleration efficiency.

Prominence instability and CMEs triggered by massive coronal rain in the solar atmosphere

Context. The triggering process for prominence instability and consequent coronal mass ejections (CMEs) is not fully understood. Prominences are maintained by the Lorentz force against the gravity; therefore, reduction of the prominence mass due to the coronal rain may cause the change of the force balance and hence destabilisation of the structures. Aims. We aim to study the observational evidence of the influence of coronal rain on the stability of prominence and subsequent eruption of CMEs. Methods. We used the simultaneous observations from the Atmospheric Imaging Assembly (AIA) of Solar Dynamics Observatory (SDO) and Sun Earth Connection Coronal and Heliospheric Investigation (SECHHI) of Solar Terrestrial Relations Observatory (STEREO) spacecrafts from different angles to follow the dynamics of prominence and to study the role of coronal rain in their destabilisation. Results. Three different prominences observed during the years 2011–2012 were analysed using observations acquired by SDO and STEREO. In all three cases, massive coronal rain from the prominence body led to the destabilisation of prominence and subsequently to the eruption of CMEs. The upward rising of prominences consisted of the slow and fast rise phases. The coronal rain triggered the initial slow rise of prominences, which led to the final instability (the fast rise phase) after 18–28 h in all cases. The estimated mass flux carried by coronal rain blobs showed that the prominences became unstable after 40% of mass loss. Conclusions. We suggest that the initial slow rise phase was triggered by the mass loss of prominence due to massive coronal rain, while the fast rise phase (the consequent instability of prominences) was caused by the torus instability and/or magnetic reconnection with the overlying coronal field. Therefore, the coronal rain triggered the instability of prominences and consequent CMEs. If this is the case, then the coronal rain can be used to predict the CMEs and hence to improve the space weather predictions.

Energy Supply to Buses on a Conductive Electric Road: An Evaluation of Charger Topologies and Electric Road Characteristics

An electric road system (ERS) enables transfer of electric energy to a moving vehicle, making it possible to reduce the capacity—and cost—of the battery and the need for static chargers. A conductive electric road allows for relatively low complexity whilst being able to provide high levels of power. When utilising a conductive electric road, safety precautions must be considered with regard to isolation between the charging supply (the electric road) and the vehicle’s traction voltage system (TVS), since no protective Earth connection can be guaranteed. Isolation can be achieved by separating the two systems galvanically or by double isolating the entire TVS and all equipment connected to it on-board the vehicle. This study used the experimental results from a previous paper to model and evaluate three different electric powertrains/charger topologies, including a novel integrated design fulfilling the required safety features. The models were used in a full vehicle model and further investigated in a city bus scenario in terms of how charging performance, energy consumption and battery ageing are affected by the aforementioned charging topologies and electric road characteristic. We discovered that charging topology has a strong influence on energy consumption, and that electric road characteristics have a strong influence on battery ageing.

Laminar and turbulent plasmoid ejection in a laboratory Parker Spiral current sheet

Quasi-periodic plasmoid formation at the tip of magnetic streamer structures is observed to occur in experiments on the Big Red Ball as well as in simulations of these experiments performed with the extended magnetohydrodynamics code, NIMROD. This plasmoid formation is found to occur on a characteristic time scale dependent on pressure gradients and magnetic curvature in both experiment and simulation. Single mode, or laminar, plasmoids exist when the pressure gradient is modest, but give way to turbulent plasmoid ejection when the system drive is higher, which produces plasmoids of many sizes. However, a critical pressure gradient is also observed, below which plasmoids are never formed. A simple heuristic model of this plasmoid formation process is presented and suggested to be a consequence of a dynamic loss of equilibrium in the high- $\beta$ region of the helmet streamer. This model is capable of explaining the periodicity of plasmoids observed in the experiment and simulations, and produces plasmoid periods of 90 minutes when applied to two-dimensional models of solar streamers with a height of $3R_\odot$ . This is consistent with the location and frequency at which periodic plasma blobs have been observed to form by Large Angle and Spectrometric Coronograph and Sun Earth Connection Coronal and Heliospheric Investigation instruments.

Radial velocity map of solar wind transients in the field of view of STEREO/HI1 on 3 and 4 April 2010

Context. The solar wind transients propagating out in the inner heliosphere can be observed in white-light images from Heliospheric Imager-1 (HI1), an instrument of the Sun Earth Connection Coronal and Heliospheric Investigation on board the Solar Terrestrial Relations Observatory (STEREO), from two perspectives. The spatial velocity distribution inside solar wind transients is key to understanding their dynamic evolution processes. Aims. We generated a velocity map of transients in 3D space based on 2D white-light images and used it to estimate the expansion rate as well as some kinematic properties of solar wind transients. Methods. Based on the recently developed correlation-aided reconstruction method in our previous work, which can recognize and locate 3D solar wind transients from STEREO/HI1 image data, we further developped a new technique for deriving the spatial distribution of the radial velocities of the most pronounced features inside solar wind transients. Results. The technique was applied to events including a coronal mass ejection (CME) and three small-scale transients, so-called blobs, observed by HI1 on 3–4 April 2010 to reconstruct their radial velocity maps. The results match the forward-modeling results, simulations, and in situ observations at 1 AU fairly well. According to the obtained spatial distributions of height and radial velocity of the CME, we analyzed the self-similarity of the radial expansion of the CME ejecta. The dimensionless radial expansion rate of the northern and middle parts of the CME ejecta varies in the range of 0.7−1.0 at heliocentric distance between 25 R⊙ and 55 R⊙ and the rate of the southern part in the range of 0.3−0.5, suggesting that the CME structure was distorted and shaped by the ambient solar wind. The technique we developed is expected to be applied to more events.

Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view

Solar energetic particles (SEPs) accelerated from shocks driven by coronal mass ejections (CMEs) are one of the major causes of geomagnetic storms on Earth. Therefore, it is necessary to predict the occurrence and intensity of such disturbances. For this purpose we analyzed in detail 38 non-interacting halo and partial halo CMEs, as seen by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph, generating SEPs (in &gt; 10 MeV, &gt; 50 MeV, and &gt; 100 MeV energy channels) during the quadrature configuration of the Solar TErrestrial RElations Observatory (STEREO) twin spacecrafts with respect to the Earth, which marks the ascending phase of solar cycle 24 (i.e., 2009–2013). The main criteria for this selection period is to obtain height–time measurements of the CMEs without significant projection effects and in a very large field of view. Using the data from STEREO/Sun Earth Connection Coronal and Heliospheric Investigation (STEREO/SECCHI) images we determined several kinematic parameters and instantaneous speeds of the CMEs. First, we compare instantaneous CME speed and Mach number versus SEP fluxes for events originating at the western and eastern limb; we observe high correlation for the western events and anticorrelation for the eastern events. Of the two parameters, the Mach number offers higher correlation. Next we investigated instantaneous CME kinematic parameters such as maximum speed, maximum Mach number, and the CME speed and Mach number at SEP peak flux versus SEP peak fluxes. Highly positive correlation is observed for Mach number at SEP peak flux for all events. The obtained instantaneous Mach number parameters from the emperical models was verified with the start and end time of type II radio bursts, which are signatures of CME-driven shock in the interplanetary medium. Furthermore, we conducted estimates of delay in time and distance between CME, SEP, and shock parameters. We observe an increase in the delay in time and distance when SEPs reach peak flux with respect to CME onset as we move from the western to the eastern limb. Western limb events (longitude 60°) have the best connectivity and this decreases as we move towards the eastern limb. This variation is due to the magnetic connectivity from the Sun to the Earth, called the Parker spiral interplanetary magnetic field. Comparative studies of the considered energy channels of the SEPs also throw light on the reacceleration of suprathermal seed ions by CME-driven shocks that are pre-accelerated in the magnetic reconnection.

Light symbolism of female mythological images as a spiritual foundation of Japanese and Chinese cultures

This article analyzes female principle reflected in the images of goddesses of Japanese and Chinese mythology associated with the solar cult and light symbolism. An attempt is made to trace the role of female principle in the mythological phenomenon of Sky and its connection with Earth. The subject of this research is the Japanese and Chinese myths and legends, iconographic images of goddesses and their resemblance in foxes (Kitsune) in the religious painting of the XIII &amp;ndash; early XX centuries. In the course of this work, the author applies comparative-historical and iconographic methods of research that lean on scientific materials dedicated to philosophy, culturology and art history. The relevance of the selected topic is substantiated by the fact that in globalizing world, the countries of the Far East are more capable of retaining ideological paradigms and preserving their national cultural identity due to traditionalism and spiritual consciousness. The novelty of this work consists in examination based on the iconographic material and mythological themes of solar manifestations of goddesses as demonstration of the energy of female principle and its reflection in the phenomenon of Sky &amp;ndash; Earth connection. The conclusion is made that for assessing Japanese and Chinese art, it is essential to consider multicultural interaction of these countries founded on the the harmony of existence of human nature. The goddesses of Sun, Moon and Earth seek to communicate with the Sky, as in particular the autochthonous deity Inari through their intermediaries, the foxes. The sun and moon goddesses and Earth goddesses seek communication with the Sky, as the autochthonous deity Inari through their mediators &amp;ndash; foxes. The female principle, resembled in femininity of divine foxes, is described as the endless struggle for immortality and opportunity to be in Heaven surrounded by the steam light and reason. The light saturation of female images contributes to their spirituality.

Earth connection

This study explored direct experiences of women’s relationships with the Earth and how this impacted their lives. Using the transpersonal research methodology of intuitive inquiry, 10 White Western women aged between 36 and 64 were interviewed. Thematic content analysis was used to identify the emerging themes within the data and create descriptive summaries. The research found that connecting to the Earth may help us (a) process difficult emotions and experience more positive ones; (b) stay present and deal with life more effectively; (c) feel in control of changes in our lives; (d) realise that we need to give back to the Earth for what it provides for us; (e) expand our sense of self to include a sense of a divine cycle of life, and; (f) feel part of the Earth as we develop a clearer sense of who we are on an individual level. A definition of Earth connection is proposed: Earth connection is a subjective sense of feeling part of the Earth. It helps an individual to gain a deeper sense of who they are within a divine cycle of life. It also promotes a sense of a reciprocal relationship between an individual and the Earth.

Influence of the earth connections of the PWM drive on the voltage constraints endured by the motor insulation

AbstractThe high electrical stresses in the Electrical Insulation Systems of machines fed by pulse width modulation (PWM) inverters remain a limitation of the lifetime. The stress is caused by repetitive over voltages caused by the short switching times of the PWM inverter power electronic circuit. This paper provides measurements made on an industrial drive connected to the grid with standard cables that include a ground connection wire, following the current standards. The phase-to-phase, phase-to-neutral, and neutral-to-ground voltages are measured focusing on short and repetitive voltage spikes. The causes of these voltage spikes are analyzed using a high frequency equivalent circuit of the whole drive, including the earthing system. The simulations are made with the well-known SPICE circuit simulator. This study focuses on the common-mode currents flowing in the earthing connections and its influence on voltage spikes. A solution that can reduce significantly the phase-to-neutral voltage spikes is proposed.