Slow Wind Speed Research Articles

Constraining Suprathermal Electron Evolution in a Parker Spiral Field With Cassini Observations

AbstractSuprathermal electrons in the solar wind consist of the “halo,” present at all pitch angles, and the “strahl” which is a field‐aligned, beam‐like population. Examining the heliospheric evolution of strahl beams is key to understanding the in‐transit processing of solar wind suprathermal electrons, in particular, to identify electron scattering mechanisms and to establish the origin of the halo population. Not only does this have significant implications with regard to the kinetic processes occurring within the solar wind but also its thermodynamic evolution, as the suprathermal electrons carry the majority of the solar wind heat flux. In this investigation, an established model for suprathermal electron evolution in a Parker spiral interplanetary magnetic field is adapted from its original use. The model is constrained using solar wind strahl observed by the Cassini mission on its interplanetary journey to Saturn. The effects of large scale IMF geometry due to different solar wind velocities and application of different electron scattering factors are examined. It is found that slow solar wind speeds provide the closest match to the strahl width observations, both in terms of radial distance and electron energy trends, and that predominantly slower solar wind speeds were therefore likely observed by the Cassini mission en‐route to Saturn. It is necessary to include a strahl scattering factor which increases with electron energy in order to match observations, indicating that the strahl scattering mechanism must have an inherent energy dependence.

Acoustic Emission Analysis for Wind Turbine Blade Bearing Fault Detection Under Time-Varying Low-Speed and Heavy Blade Load Conditions

This article uses acoustic emission (AE) analysis to diagnose an industrial-scale and slow-speed wind turbine blade bearing. The main challenge for AE analysis is that the fault signals are mingled with heavy noise. As a result, the objective of this article is to filter the raw AE signals and extract weak fault signals. To achieve this goal, a general linear and nonlinear auto-regressive (GLNAR) model is first developed to exploit the nonlinear characteristics of the AE signals. Then, the sparse augmented Lagrangian (SAL) algorithm is applied to learn the built GLNAR model and filter the raw AE signals. The characteristics of SAL is that it is a novel sparse representation technique which can convert the original filtering problem into a number of suboptimization problems, and these subproblems can be solved separately. Finally, as the blade bearing rotates at fluctuating speeds, the filtered signals are resampled so that the bearing fault type can be diagnosed in the order domain. The proposed diagnostic framework was validated in several experiments under time-varying low-speed and heavy-blade-load conditions. The results indicate that our proposed methods are effective and accurate.

Design of small scale, axial flux, permanent magnet wind generator in Vietnam

This paper presents the design of light weight, small scale, disk type, axial flux, permanent magnet (AFPM) generator for wind applications. This article also shows the partial works done under state projects in renewable energy in Vietnam to find out the most suitable, reliable, self - made wind generator types for rural and remote areas. The collaboration project of Hochiminh City University (HCMUT) - Hanoi University of Science and Technology (HUST) - Berlin University of Technology (TU Berlin) resulted in some small scale, axial flux, slow speed, permanent magnet (PM) generators which best suited for Vietnam countryside areas. The researches in rare earth PM from HUST, the electrical machine design knowhow of TU Berlin and the renewable energy research experiences of HCMUT, especially in slow speed wind turbines have shown many promising applications. The small scale, permanent magnet wind generator for remote and rural areas as a cheap source of power supply is necessary in Vietnam. Though there are many large wind farms built in many provinces recently but the needs for telecommunication, family lighting in the heights, mountain, unreachable electric grid communes are still necessary. Further research should be done to match the generator for hydro power stations, diesel coupled internal combustion engine. These prospects are very promising.

Techno-Economic Feasibility Analysis of Concentrated Solar Thermal Power Plants as Dispatchable Renewable Energy Resource of Pakistan: A case study of Tharparkar

Pakistan is identified to be one of the next-11 the top emerging economies of the world after the BRICS. This emphasizes the establishment of a competitive electricity market that can fulfil the demand of the country considering the environmental concerns. In this scenario reliability of power is something that cannot be compromised. Dispatchable power stations play a major role in balancing supply and demand; this balance is essential for maintaining the power cuts free country. All dispatchable power stations incorporate some form of storage particularly thermal or chemical (i.e. a stored fuel). Earlier dispatchable power was regarded as the generation which can start quickly and meet the peak demand requirements but arrival of renewables in power system has increased worth of its presence since it has just not to supply peak demand but also to meet during the unavailability of other renewable energy sources because of their intermittent behavior meanly at times of dark hours and slow wind speed. This study considers the viability of Concentrated Solar Thermal Power in Pakistan and thoroughly analyses several characteristics i.e., Availability of fuel, water, road and communication network, flexibility and environmental impacts of the technology for the cite of Tharparkar.

Fault Diagnosis of Industrial Wind Turbine Blade Bearing Using Acoustic Emission Analysis

Wind turbine blade bearings are often operated in harsh circumstances, which may easily be damaged causing the turbine to lose control and to further result in the reduction of energy production. However, for condition monitoring and fault diagnosis (CMFD) of wind turbine blade bearings, one of the main difficulties is that the rotation speeds of blade bearings are very slow (less than 5 r/min). Over the past few years, acoustic emission (AE) analysis has been used to carry out bearing CMFD. This article presents the results that reflect the potential of the AE analysis for diagnosing a slow-speed wind turbine blade bearing. To undertake this experiment, a 15-year-old naturally damaged industrial and slow-speed blade bearing is used for this study. However, due to very slow rotation speed conditions, the fault signals are very weak and masked by heavy noise disturbances. To denoise the raw AE signals, we propose a novel cepstrum editing method, discrete/random separation-based cepstrum editing liftering (DRS-CEL), to extract weak fault features from raw AE signals, where DRS is used to edit the cepstrum. Thereafter, the morphological envelope analysis is employed to further filter the residual noise leaked from DRS-CEL and demodulate the denoised signal, so the specific bearing fault type can be inferred in the frequency domain. The diagnostic framework combining DRS-CEL and morphological analysis is validated by comparing several methods and related studies, which offers a promising solution for wind-farm applications.

Coronal Electron Density Fluctuations Inferred from Akatsuki Spacecraft Radio Observations

Trans-coronal radio observations were taken during the 2011 observing campaign of the Akatsuki spacecraft through superior conjunction. The observed X-band (8.4 GHz) signals exhibit frequency fluctuations (FF) that are produced by temporal variations in electron density along the radio ray path. A two-component model for interpretation of the FF is proposed: FF scales largely with acoustic wave amplitude through the inner coronal regions where the sound speed dwarfs the solar wind outflow speed, while FF in the region of solar wind acceleration is dominated by the increased density oscillation frequency on the sensing path that results from bulk advection of the plasma inhomogeneities. An estimate of fractional electron density fluctuation is obtained from the mid-corona. A radial profile of slow solar wind speed is determined in the extended corona using mass-flux continuity principles. The coronal sonic point for slow solar wind is estimated to range from 4 to 5 solar radii from the heliocenter.

Two Wolf–Rayet stars at the heart of colliding-wind binary Apep

ABSTRACT Infrared imaging of the colliding-wind binary Apep has revealed a spectacular dust plume with complicated internal dynamics that challenges standard colliding-wind binary physics. Such challenges can be potentially resolved if a rapidly rotating Wolf–Rayet star is located at the heart of the system, implicating Apep as a Galactic progenitor system to long-duration gamma-ray bursts. One of the difficulties in interpreting the dynamics of Apep is that the spectral composition of the stars in the system was unclear. Here, we present visual to near-infrared spectra that demonstrate that the central component of Apep is composed of two classical Wolf–Rayet stars of carbon- (WC8) and nitrogen-sequence (WN4-6b) subtypes. We argue that such an assignment represents the strongest case of a classical Wolf–Rayet+Wolf–Rayet binary system in the Milky Way. The terminal line-of-sight wind velocities of the WC8 and WN4-6b stars are measured to be 2100 ± 200 and 3500 ± 100 km s−1, respectively. If the mass-loss rate of the two stars are typical for their spectral class, the momentum ratio of the colliding winds is expected to be ≈0.4. Since the expansion velocity of the dust plume is significantly smaller than either of the measured terminal velocities, we explore the suggestion that one of the Wolf–Rayet winds is anisotropic. We can recover a shock-compressed wind velocity consistent with the observed dust expansion velocity if the WC8 star produces a significantly slow equatorial wind with a velocity of ≈530 km s−1. Such slow wind speeds can be driven by near-critical rotation of a Wolf–Rayet star.

Fitting of Weibull Distribution Method to Analysis Wind Energy Potential at Kuala Terengganu, Malaysia

Malaysia faces many challenges in the development of wind energy as it is located in areas with slower wind speeds. Malaysia is located on the equator line where land and sea breezes can affect the wind regime. The wind does not blow uniformly and fluctuates by month and area. Therefore, the objective of this study is to determine the potential of the latest wind power in Kuala Terengganu, Malaysia which is located at latitude 5° 23' N and longitude 103° 06' E. by using Weibull Distribution method. The wind data used in this study was obtained from the Malaysian Meteorological Department. The daily wind speed pattern for the year 2017 can be seen that it has a corresponding pattern where it shows high wind speed at the beginning and end of the year. The wind speed frequency is also variable for the winds of the Northeast Monsoon and is almost constant during the south monsoon of the Southwest Monsoon and the Transition Monsoon. Overall, the potential for wind power in Kuala Terengganu is not too large. The annual average for 2017 is 2.01 m/s only. Wind power is high during the Northeast Wind Monsoon season.

Potential Evaluation of Wind Energy in Kuala Terengganu, Malaysia through Weibull Distribution Method

Malaysia faces many challenges in the development of wind energy as it is located in areas with slower wind speeds. Malaysia is located on the equator line where land and sea breezes can affect the wind regime. The wind does not blow uniformly and fluctuate by month and area. Therefore, the objective of this study is to determine the potential of the latest wind power in Kuala Terengganu. The scope of the study was not comprehensive because it focused only on Kuala Terengganu, Malaysia which is located at latitude 5° 23′ N and longitude 103° 06′ E. The wind data used in this study was obtained from the Malaysian Meteorological Department. The wind data that had been observed and collected was the wind direction and wind speed for year 2017 where the height of the sea level is 5.2 meters. This study uses the Weibull Distribution method as it shows a good consideration to estimate the density of wind power in Malaysia [1] The daily wind speed pattern for year 2017 can be seen that it has a corresponding pattern where it shows high wind speed at the beginning and end of the year. The wind speed frequency is also variable for the winds of the Northeast Monsoon and is almost constant during the south monsoon of the Southwest Monsoon and the Transition Monsoon. Overall, the potential of wind power in Kuala Terengganu is not too large. The annual average for 2017 is 2.01 m/s only. Wind power is high during the Northeast Wind Monsoon season.

서울지역 PM2.5 오염원의 시계열적 기여도 평가와 헤이즈의 유형분류

Huge hourly PM2.5 datasets monitored at the Seoul Intensive Monitoring Station (SIMS) during Jan. 1, 2013 to Dec. 31, 2014 were obtained from the National Institute of Environmental Research (NIER). A total of 12,376 samples consisting of 24 chemical variables and 3 meteorological variables had been applied for the positive matrix factorization (PMF) modeling based on a dataset segmentation scheme in the previous study (Park et al., 2019). After performing the receptor model, 14 independent PM2.5 sources were successfully identified and quantified at the SIMS. In this study, based on the meteorological variables and the previous PMF results, we assessed intensively the PM2.5 source contributions by time sequential analyses such as hourly, daily, weekly, monthly, and seasonal analyses and further we classified haze patterns into 3 types such as foreign-oriented type, domestic-oriented type, and mixed type, judging from PM2.5 source contribution. According to our intensive study on wintertime haze cases, all the episode events in Seoul area initially began with rapid and big air temperature drop for several days and then high PM2.5 concentration appeared right after rapid and big air temperature rise until air temperature rose again, which forming frontal inversion with slower wind speed and then lowering a mixing height causing concentration buildup. The most dominant PM2.5 source among 14 identified sources in Seoul area was secondary aerosol source, which was considered to be transported distantly from overseas. The seasonal source contribution was summer 15.8 μg/m³, spring 14.4 μg/m³, winter 10.4 μg/m³, and fall 5.4 μg/m³ in mass order. On the other hand, secondary nitrate source as another secondary aerosol was identified as one of domestic sources. The range of seasonal source contribution was in the range of 1.0∼2.4 μg/m³ and further weekly and monthly variations were relatively small. However, its hour variation was greatly changed, up to 4.5 μg/m³ during nighttime. We hope that the results of the study can be used as basic information whenever establishing reasonable air quality management and policy in Korea.

Wind and Solar Assessment in the Sahelian Zone of Chad

Renewable energy sources have long been renowned as potential sources of free, clean and inexhaustible energy. However, energy in Chad is still exploited from non-renewable sources due to lack of comprehensive wind and solar maps, skills and public awareness pertaining to its significance in the country. This study is therefore set out to provide assessments of both wind and solar energies in the Sahelian zone in Chad, using the statistical two-parameter Weibull distribution function and Angstrom-Prescott model, respectively for a ten-year period. The evaluation of wind potential shows that the annual mean of the shape and scale parameters for all stations under study varied in the range of 1.26 – 1.56 and 2.49 m/s – 3.91 m/s, respectively. Stronger wind speed was observed during the dry season and a relatively slower wind speed was perceived during the wet season. Among the four stations, N’Djamena showed the highest power density compared to the other three stations with a mean power density that ranges between 100 W/m 2 – 220 W/m 2 . The prediction of solar potential in this region indicates that the global solar radiation for all stations is promising with station Abeche however, to show the highest solar energy density on average. A good agreement between Angstrom model and NASA data was also observed.

Three-phase Evolution of a Coronal Hole. I. 360° Remote Sensing and In Situ Observations

Abstract We investigate the evolution of a well-observed, long-lived, low-latitude coronal hole (CH) over 10 solar rotations in the year 2012. By combining extreme ultraviolet (EUV) imagery from the Solar TErrestrial RElations Observatories (STEREO-A/B) and the Solar Dynamics Observatory (SDO), we are able to track and study the entire evolution of the CH having a continuous 360° coverage of the Sun. The remote sensing data are investigated together with in situ solar wind plasma and magnetic field measurements from STEREO-A/B, the Advanced Composition Explorer (ACE), and WIND. From this, we obtain how different evolutionary states of the CH as observed in the solar atmosphere (changes in EUV intensity and area) affect the properties of the associated high-speed stream measured at 1 au. Most distinctly pronounced for the CH area, three development phases are derived: (a) growing, (b) maximum, and (c) decaying phase. During these phases the CH area (a) increases over a duration of around three months from about 1 · 1010 km2 to 6 · 1010 km2, (b) keeps a rather constant area for about one month of >9 · 1010 km2, and (c) finally decreases in the following three months below 1 · 1010 km2 until the CH cannot be identified anymore. The three phases manifest themselves also in the EUV intensity and in in situ measured solar wind proton bulk velocity. Interestingly, the three phases are related to a different range in solar wind speed variations, and we find for the growing phase a range of 460–600 km s−1, for the maximum phase 600–720 km s−1, and for the decaying phase a more irregular behavior connected to slow and fast solar wind speeds of 350–550 km s−1.

Developing the full-field wind generator integrated with the vertical twin rotors

This research aims to develop a full-field wind generator integrated with a vertical twin rotor that the applied generator uses a variable normal rated power and driven by a vertical twin rotor. This developed windmill is with a complex structure which combines both Savonius and Darrieus blades. During the working process, the Savonius blade is driven by a slower wind speed and promotes the Darrieus blade to reduce its starting wind speed. The Darrieus blade then drives the electric generator. Rotation of the two blades will be separated in a high speed wind field to reduce the wind resistance of the windmill. The efficiency of multi-layer magnetic electric machine can achieve to 84% at 200 rpm, 81.1% at 300 rpm, even 80% at 400–900 rpm. Also, the automatic control load has a better efficiency which is a 3% difference compared with the fixed load operation and the maximum efficiency can be up to 19.11%.

An inverse method to estimate emission rates based on nonlinear least-squares-based ensemble four-dimensional variational data assimilation with local air concentration measurements

An inverse source estimation method is proposed to reconstruct emission rates using local air concentration sampling data. It involves the nonlinear least squares-based ensemble four-dimensional variational data assimilation (NLS-4DVar) algorithm and a transfer coefficient matrix (TCM) created using FLEXPART, a Lagrangian atmospheric dispersion model. The method was tested by twin experiments and experiments with actual Cs-137 concentrations measured around the Fukushima Daiichi Nuclear Power Plant (FDNPP). Emission rates can be reconstructed sequentially with the progression of a nuclear accident, which is important in the response to a nuclear emergency. With pseudo observations generated continuously, most of the emission rates were estimated accurately, except under conditions when the wind blew off land toward the sea and at extremely slow wind speeds near the FDNPP. Because of the long duration of accidents and variability in meteorological fields, monitoring networks composed of land stations only in a local area are unable to provide enough information to support an emergency response. The errors in the estimation compared to the real observations from the FDNPP nuclear accident stemmed from a shortage of observations, lack of data control, and an inadequate atmospheric dispersion model without improvement and appropriate meteorological data. The proposed method should be developed further to meet the requirements of a nuclear emergency response.

Theoretical analysis of the effects of irrigation rate and paddy water depth on water and leaf temperatures in a paddy field continuously irrigated with running water

Water management techniques such as continuous irrigation with running water (CIRW) have been used by Japanese farmers to control the thermal environment for rice cropping. In this study, to optimize this method to control the thermal environment in paddy fields, theoretical equations for predicting water and vegetation temperatures in a paddy field were obtained. First, the equations to calculate water and vegetation temperatures in a paddy field were obtained by solving the heat balance equations of the paddy water and vegetation, taking into account the effect of horizontal heat convection driven by irrigation. The equations were validated by comparisons with observed water temperatures in a conventional paddy field under CIRW. The calculated changes in water temperatures over time and distance showed good agreement with observed values, with a root mean square error of 0.39°C. This result indicated that the equations satisfactorily expressed the features of paddy water temperature under CIRW. Next, these equations were used to determine the effects of irrigation rate, paddy water depth and wind speed on water and rice plant temperatures. The following results were obtained. 1) The area cooled by CIRW was positively related to irrigation rate and negatively related to water depth. 2) Low water depths were preferable for application of CIRW during the nighttime. 3) Slower wind speeds and latent heat flux from vegetation strengthened the effects of water management on vegetation temperature. The proposed equations and analyses represent the common features of the effect of irrigation on water and vegetation temperatures in a paddy field, and provide quantitative information about the effects of water management techniques on the thermal environment for rice cropping.

Solar Radiation and Urban Wind Effect on Urban Canyon in Hot, Humid Regions

Urban configuration modification is an efficient approach to mitigating Urban Heat Island effect. This study investigates the significant impact of solar radiation and urban wind on microclimate and thermal comfort in the different setting of urban canyon configuration. The Envi-met (V3.1 beta) simulation presents that East-West canyon direction received the worst level of air temperature and meant radiant temperature compared to when the canyon was directed perpendiculars to the wind direction (South East – North West). The finding scientifically demonstrates that in Kuala Lumpur context, with the slow urban wind speed influences, solar radiation plays the significant impact on the microclimate.© 2016. The Authors. Published for AMER ABRA by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.Keywords: Solar radiation; urban wind; urban microclimate, urban simulation

Modification and Testing of Wind Turbine with Double Savonius

Indonesia geographically located at tropical region where the wind is very fluctuate and relatively slow. Therefore it is important for designer to investigate the proper design of the slow wind speed turbine that applicable in Indonesia. In this paper, Savonius wind turbine is selected and modified with double level to explore its capability in generating voltage. The main aim of this study is to investigate the performance of the double Savonius turbine in term of its capability in generating voltage. In experimental test, it can be obtained that the double Savonius Turbine could effectively generate 12V at 3 m/s and 17V at 5.4 m/s.

The Horizontal and Vertical Characteristics of Aeolian Dust from Riverbed

ABSTRACTArid riverbed is an important source of Aeolian dust to influence the atmosphere of nearby village or downtown. In general, Aeolian dust pertains to wind activity in the study of geology, environment and meteorology on particle suspension. This field study set the horizontal/vertical sampling system up in order to investigate the Aeolian dust dimensional distribution properties from the riverbed of the Jhuoshuei River. In addition, the study utilized the unmanned aerial vehicle (UAV) imagery to discriminate the covering condition of riverbed. The results revealed that the percentage of riverbed covering conditions, including bare zone, wetlands, green covering and water covering was about 50.1, 15.7, 16.8 and 17.4%, respectively, on January 5th, 2011. Two Aeolian dust cases from riverbed were measured on November 26th, 2010 and January 15th, 2011. First sampling case was under slower wind speed, and the total particulate matter (PM) concentration in vertical sampling was almost decreased with increasing sampling height, however, the phenomena of second case (faster wind speed) was just on the contrary. Besides, Aeolian dust was distributed in a bimodal or a multimodal curve, and the main peak size was above 10 μm. Mode size of suspension particle diameter was increased as the wind speed increased (14.8 μm/ first case; 21.3 μm/ second case). The total mass concentration ratio of south site to source site (one meter height) was about 1:9 in first case and about 1:3 in second case. Comparing with those two cases, the faster the wind is, the shorter the surface roughness height is (3.08 mm/ first case; 1.07 mm/ second case). Besides, as the wind speed increasing, the friction velocity was also increased (0.33 m s–1/ first case; 0.68 m s–1/ second case). Consequently, this study clued the spatial variability of river dust events, which can further aid the site investigating, forecasting and preventing of dust influences.

Connecting the dots – II. Phase changes in the climate dynamics of tidally locked terrestrial exoplanets

We investigate 3D atmosphere dynamics for tidally locked terrestrial planets with an Earth-like atmosphere and irradiation for different rotation periods ($P_{rot}=1-100$ days) and planet sizes ($R_P=1-2 R_{Earth}$) with unprecedented fine detail. We could precisely identify three climate state transition regions that are associated with phase transitions in standing tropical and extra tropical Rossby waves. We confirm that the climate on fast rotating planets may assume multiple states ($P_{rot}\leq 12$ days for $R_P=2 R_{Earth}$). Our study is, however, the first to identify the type of planetary wave associated with different climate states: The first state is dominated by standing tropical Rossby waves with fast equatorial superrotation. The second state is dominated by standing extra tropical Rossby waves with high latitude westerly jets with slower wind speeds. For very fast rotations ($P_{rot}\leq 5$~days for $R_P=2 R_{Earth}$), we find another climate state transition, where the standing tropical and extra tropical Rossby wave can both fit on the planet. Thus, a third state with a mixture of the two planetary waves becomes possible that exhibits three jets. Different climate states may be observable, because the upper atmosphere's hot spot is eastward shifted with respect to the substellar point in the first state, westward shifted in the second state and the third state shows a longitudinal 'smearing' of the spot across the substellar point. We show, furthermore, that the largest fast rotating planet in our study exhibits atmosphere features known from hot Jupiters like fast equatorial superrotation and a temperature chevron in the upper atmosphere.

The FIP and Inverse FIP Effects in Solar and Stellar Coronae

We review our state of knowledge of coronal element abundance anomalies in the Sun and stars. We concentrate on the first ionization potential (FIP) effect observed in the solar corona and slow-speed wind, and in the coronae of solar-like dwarf stars, and the "inverse FIP" effect seen in the corona of stars of later spectral type; specifically M dwarfs. These effects relate to the enhancement or depletion, respectively, in coronal abundance with respect to photospheric values of elements with FIP below about 10~eV. They are interpreted in terms of the ponderomotive force due to the propagation and/or reflection of magnetohydrodynamic waves in the chromosphere. This acts on chromospheric ions, but not neutrals, and so can lead to ion-neutral fractionation. A detailed description of the model applied to closed magnetic loops, and to open field regions is given, accounting for the observed difference in solar FIP fractionation between the slow and fast wind. It is shown that such a model can also account for the observed depletion of helium in the solar wind. The helium depletion is sensitive to the chromospheric altitude where ion-neutral separation occurs, and the behavior of the helium abundance in the closed magnetic loop strongly suggests that the waves have a coronal origin. This, and other similar inferences may be expected to have a strong bearing on theories of solar coronal heating. Chromospheric waves originating from below as acoustic waves mode convert, mainly to fast mode waves, can also give rise to ion-neutral separation. Depending on the geometry of the magnetic field, this can result in FIP or Inverse FIP effects. We argue that such configurations are more likely to occur in later-type stars (known to have stronger field in any case), and that this explains the occurrence of the Inverse FIP effect in M dwarfs.