Solar Wind Kinetic Energy Research Articles

Martian global current systems and related solar wind energy transfer: hybrid simulation under nominal conditions

ABSTRACT The magnetized solar wind drives a current system around Mars that maintains its induced magnetosphere. The solar wind also transfers its energy to the atmospheric ions, causing continuous atmospheric erosion, which has a profound impact on the planet’s evolution history. Here, we use Amitis, a Graphics Processing Unit (GPU)-based hybrid plasma model to first reproduce the global pattern of the net electric current and ion currents under an interplanetary magnetic field perpendicular to the solar wind flow direction. The resultant current distribution matches the observations and reveals more details. Using the electric field distribution characterized earlier with the same model, we calculate for the first time the spatial distribution of energy transfer rate to the plasmas in general and to different ion species at Mars. We find out that (1) the solar wind kinetic energy is the dominant energy source that drives Martian induced magnetosphere, (2) the energy flux of the shocked solar wind flows from the magnetic equatorial plane towards the plasma sheet in the induced magnetotail, (3) both the bow shock and the induced magnetospheric boundary are dynamos where plasma energy is transferred to the electromagnetic field, and (4) the planetary ions act as loads and gain energy from the electromagnetic field. The most intense load region is the planetary ion plume. The general pattern of the energy transfer rate revealed in this study is common for induced magnetospheres. Its variabilities with the upstream conditions can provide physical insight into the observed ion escape variabilities.

Development and performance assessment of a calcium-iron bromide cycle-based hydrogen production integrated system

In this study, a novel renewable energy-based trigeneration system integrated with a thermochemical cycle is newly developed, analyzed, and evaluated to determine its performance for residential applications. Both solar radiation and wind kinetic energy are harnessed for electricity production. A newly developed biomass-driven thermochemical cycle for hydrogen generation and potential blending with natural gas is analyzed and evaluated accordingly. The blend is then potentially supplied to the gas engine and some residential appliances, such as combi boilers and gas stoves to provide necessary electricity and heat. The heat obtained from the subsystems is employed for residential heating and cooking, as well as for a distillation unit. The reverse osmosis and multi-effect distillation units are both considered in an integrated fashion to produce fresh water for a community considered which consists of 10,000 houses. A total amount of 14.2 million m3 of the blend (with a ratio of 20% of hydrogen and 80% of natural gas) is annually available to potentially utilize for household appliances and gas engines. Furthermore, the present integrated system is analyzed through both energy and exergy approaches. Some parametric studies are then performed for different hydrogen fractions, hydrogen production rates, solar PV areas, wind turbine swept areas, and the number of houses. Moreover, the overall exergetic and energetic efficiencies are determined as 21.02% and 62.61% for the presently developed system.

Hydrogen fuel and electricity generation from a new hybrid energy system based on wind and solar energies and alkaline fuel cell

Excessive consumption of fossil fuels has led to depletion of reserves and environmental crises. Therefore, turning to clean energy sources is essential. However, these energy sources are intermittent in nature and have problems meeting long-term energy demand. The option suggested by the researchers is to use hybrid energy systems. The aim of this paper is provide the conceptual configuration of a novel energy cycle based on clean energy resources. The novel energy cycle is composed of a wind turbine, solar photovoltaic field (PV), an alkaline fuel cell (AFC), a Stirling engine and an electrolyzer. Solar PV and wind turbine convert solar light energy and wind kinetic energy into electricity, respectively. Then, the generated electricity is fed to water electrolyzer. The electrolyzer decomposes water into oxygen and hydrogen gases by receiving electrical power. So the fuel cell inlets are provided. Next, the AFC converts the chemical energy contained in hydrogen into electricity during electrochemical reactions with by-product (heat). The purpose of the introduced cycle is to generate electricity and hydrogen fuel. The relationships defined for the components of the proposed cycle are novel and is examined for the first time. Results showed that the output of the introduced cycle is 10.5 kW of electricity and its electrical efficiency is 56.9%. In addition, the electrolyzer uses 9.9 kW of electricity to produce 221.3 grams per hour of hydrogen fuel. The share of the Stirling engine in the output power of the cycle is 9.85% (1033.7 W) which is obtained from the dissipated heat of the fuel cell. In addition, wind turbine is capable of generating an average of 4.1 kW of electricity. However, 238.6 kW of cycle exergy is destroyed. Two different scenarios are presented for solar field design.

The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere

Abstract The first two orbits of the Parker Solar Probe spacecraft have enabled the first in situ measurements of the solar wind down to a heliocentric distance of 0.17 au (or 36 ). Here, we present an analysis of this data to study solar wind turbulence at 0.17 au and its evolution out to 1 au. While many features remain similar, key differences at 0.17 au include increased turbulence energy levels by more than an order of magnitude, a magnetic field spectral index of −3/2 matching that of the velocity and both Elsasser fields, a lower magnetic compressibility consistent with a smaller slow-mode kinetic energy fraction, and a much smaller outer scale that has had time for substantial nonlinear processing. There is also an overall increase in the dominance of outward-propagating Alfvénic fluctuations compared to inward-propagating ones, and the radial variation of the inward component is consistent with its generation by reflection from the large-scale gradient in Alfvén speed. The energy flux in this turbulence at 0.17 au was found to be ∼10% of that in the bulk solar wind kinetic energy, becoming ∼40% when extrapolated to the Alfvén point, and both the fraction and rate of increase of this flux toward the Sun are consistent with turbulence-driven models in which the solar wind is powered by this flux.

Terrestrial ion escape and relevant circulation in space

Abstract. Observations of the terrestrial ion escape to space and the transport of escaping ions in the magnetosphere are reviewed, with the main stress on subjects that were not covered in reviews over past 2 decades, during which Cluster has significantly improved our knowledge of them. Here, outflowing ions from the ionosphere are classified in terms of energy rather than location: (1) as cold ions refilling the plasmasphere faster than Jeans escape, (2) as cold supersonic ions such as the polar wind, and (3) as suprathermal ions energized by wave–particle interaction or parallel potential acceleration, mainly starting from cold supersonic ions. The majority of the suprathermal ions above the ionosphere become “hot” at high altitudes, with much higher velocity than the escape velocity even for heavy ions. This makes heavy hot ions more abundant in the magnetosphere than heavy ions transported by cold refilling ions or cold supersonic flow. The immediate destination of these terrestrial ions varies from the plasmasphere, the inner magnetosphere including those entering the ionosphere in the other hemisphere and the tailward outer boundaries, the magnetotail, and the solar wind (magnetosheath, cusp, and plasma mantle). Due to time-variable return from the magnetotail, ions with different routes and energy meet in the inner magnetosphere, making it a zoo of different types of ions in both energy and energy distribution. While the mass-independent drift theory has successfully disentangled this zoo of ions, there are many poorly understood phenomena, e.g., mass-dependent energization. Half of the heavy ions in this zoo also finally escape to space, mainly due to magnetopause shadowing (overshooting of ion drift beyond the magnetopause) and charge exchange near the mirror altitude where the exospheric neutral density is at its highest. The amount of heavy ions mixing directly with the solar wind is already the same as or larger than that entering into the magnetotail and is large enough to extract the solar wind kinetic energy in the cusp–plasma mantle through the mass-loading effect and drive the current system near the cusp independently of the global current system. Considering the past solar and solar wind conditions, ion escape might even have influenced the evolution of the terrestrial biosphere.

Behavior of Earth Magnetosphere Radius during Strong Geomagnetic Storms

Magnetosphere is a region of space surrounding Earth magnetic field, the formation of magnetosphere depends on many parameters such as; surface magnetic field of the planet, an ionized plasma stream (solar wind) and the ionization of the planetary upper atmosphere (ionosphere). The main objective of this research is to find the behavior of Earth's magnetosphere radius (Rmp) with respect to the effect of solar wind kinetic energy density (Usw), Earth surface magnetic field (Bo), and the electron density (Ne) of Earth's ionosphere for three years 2016, 2017 and 2018. Also the study provides the effect of solar activity for the same period during strong geomagnetic storms on the behavior of Rmp. From results we found that there are nonlinear relations between the (Rmp) and the three variables (Usw), (Bo) and (Ne). Also we found that during the strong geomagnetic storms there is a reduction in the radius of magnetosphere.

New Diagnosis for Energy Flow From Solar Wind to Ionosphere During Substorm: Global MHD Simulation

AbstractTo investigate the energy involved by a substorm, we performed global magnetohydrodynamics simulation for different solar wind conditions. The intensity of the auroral electrojet increases with the southward component of interplanetary magnetic field (IMF) and the solar wind velocity, which is consistent with observations. To evaluate the energy that enters the magnetosphere, we first defined a solar wind effective cross‐sectional area in which all the Poynting fluxes entering the magnetosphere pass through. We found that the solar wind magnetic energy is insufficient to provide the magnetic energy entering the magnetosphere (intake magnetic energy) for southward IMF. About 33–88% of the intake magnetic energy is converted from the solar wind kinetic energy. About 2–7% of the solar wind kinetic energy (passing through the effective area) is converted to the magnetic energy that enters the magnetosphere. Significant contribution from the solar wind kinetic energy makes the energy coupling function complicated. The effective area also depends on the solar wind parameters, also making it complicated. An interesting point is that the rates of energy stored and released in the lobe also depend on the solar wind parameters. The ionospheric Joule heating rate is well correlated with the intake magnetic energy at onset, and during the substorm expansion. The correlation coefficients between them are better than that of the ε parameter. These results imply that both the directly driven process (manifested by intake magnetic energy) and loading‐unloading process (manifested by stored/released energy in the lobe) are largely regulated by the solar wind condition.

Interstellar Medium Parameters in Front of the External Bow Shock

We know that it is the front of the Earth’s bow shock where the solar wind kinetic energy flux is transformed into the other kinds the most intensively. In our previous studies, we obtained important relationships that enable calculating the key parameters at transition through the Earth’s bow shock front. One of the most important sources of information on physical processes at the heliosphere boundary are the Voyager 1 and 2 spacecrafts. Since both the solar wind and interstellar medium are supersonic streams, two shocks are formed when flowing around the heliopause. The internal shock, in which the solar wind decelerates to subsonic velocity, is called the heliospheric shock. In the external bow shock, the interstellar gas supersonic flux is decelerated. The aim of this paper is to generalize the previously obtained equations to the processes in the external bow shock region. If Voyager-1 was equipped with a greater set of measuring instruments, we could have already provided estimations of the interstellar medium key parameters, and described in physical terms what this medium is, using relationships and equations from our studies.

Faraday rotation fluctuations of MESSENGER radio signals through the equatorial lower corona near solar minimum

AbstractFaraday rotation (FR) of transcoronal radio transmissions from spacecraft near superior conjunction enables study of the temporal variations in coronal plasma density, velocity, and magnetic field. The MESSENGER spacecraft 8.4 GHz radio, transmitting through the corona with closest line‐of‐sight approach 1.63–1.89 solar radii and near‐equatorial heliolatitudes, was recorded soon after the deep solar minimum of solar cycle 23. During egress from superior conjunction, FR gradually decreased, and an overlay of wave‐like FR fluctuations (FRFs) with periods of hundreds to thousands of seconds was found. The FRF power spectrum was characterized by a power law relation, with the baseline spectral index being −2.64. A transient power increase showed relative flattening of the spectrum and bands of enhanced spectral power at 3.3 mHz and 6.1 mHz. Our results confirm the presence of coronal FRF similar to those described previously at greater solar offset. Interpreted as Alfvén waves crossing the line of sight radially near the proximate point, low‐frequency FRF convey an energy flux density higher than that of the background solar wind kinetic energy, but only a fraction of that required to accelerate the solar wind. Even so, this fraction is quite variable and potentially escalates to energetically significant values with relatively modest changes in estimated magnetic field strength and electron concentration. Given the uncertainties in these key parameters, as well as in solar wind properties close to the Sun at low heliolatitudes, we cannot yet confidently assign the quantitative role for Alfvén wave energy from this region in driving the slow solar wind.

Energetics characteristics of the super magnetic storm on November 20, 2003 based on 3D global MHD simulation

The three-dimensional global magnetohydrodynamic model (PPM-LR MHD) is employed to investigate the energy budget in the solar wind-magnetosphere system during the super magnetic storm on November 20, 2003, one of the biggest storms during the last decade with Dst ∼ −500 nT. During this event, about 23% solar wind kinetic energy is transferred into the magnetosphere. The total energy input is estimated to be about 9.50×1017 J, about 14 times of a moderate storm. The energy dissipation via the inner magnetosphere is less than the energy input with the coupling efficiency of ∼63.3%. The energy dissipated via ring current injection is less than that via high-latitude ionosphere at the initial stage of the super storm. Furthermore, both the simulation results and the empirical results indicate that the ratio of ring current injection to the total energy output increases with the enhancement of the magnetospheric activity level. These are consistent with the statistical results we have got before. The empirical equations underestimate the solar wind kinetic energy, the energy input, and the energy dissipation via high-latitude ionosphere compared with the simulation results; however, the coupling efficiency of the high-latitude ionosphere (23.4%) is close to the simulation result (23.1%) during the entire storm time period.

Solar wind‐magnetosphere energy coupling function fitting: Results from a global MHD simulation

AbstractQuantitatively estimating the energy input from the solar wind into the magnetosphere on a global scale is still an observational challenge. We perform three‐dimensional magnetohydrodynamic (MHD) simulations to derive the energy coupling function. Based on 240 numerical test runs, the energy coupling function is given by. We study the correlations between the energy coupling function and a wide variety of magnetospheric activity, such as the indices ofDst,Kp,ap,AE,AU,AL, the polar cap index, and the hemispheric auroral power. The results indicate that this energy coupling function gives better correlations than theεfunction. This result is also applied to a storm event under northward interplanetary magnetic field conditions. About 13% of the solar wind kinetic energy is transferred into the magnetosphere and about 35% of the input energy is dissipated in the ionosphere, consistent with previous studies.

Solar wind‐magnetosphere energy coupling efficiency and partitioning: HILDCAAs and preceding CIR storms during solar cycle 23

AbstractA quantitative study on the energetics of the solar wind‐magnetosphere‐ionosphere system during High‐Intensity, Long‐Duration, Continuous AE Activity (HILDCAA) events for solar cycle 23 (from 1995 through 2008) is presented. For all HILDCAAs, the average energy transferred to the magnetospheric/ionospheric system was ~6.3 ×1016 J, and the ram kinetic energy of the incident solar wind was ~7.1 ×1018 J. For individual HILDCAA events the coupling efficiency, defined as the ratio of the solar wind energy input to the solar wind kinetic energy, varied between 0.3% and 2.8%, with an average value of ~0.9%. The solar wind coupling efficiency for corotating interaction region (CIR)‐driven storms prior to the HILDCAA events was found to vary from ~1% to 5%, with an average value of ~2%. Both of these values are lower than the> 5% coupling efficiency noted for interplanetary coronal mass ejection (and sheath)‐driven magnetic storms. During HILDCAAs, ~67% of the solar wind energy input went into Joule heating, ~22% into auroral precipitation, and ~11% into the ring current energy. The CIR‐storm Joule heating (~49%) was noticeably less than that during HILDCAAs, while the ring current energies were comparable for the two. Joule dissipation was higher for HILDCAAs that followed CIR‐storms (88%) than for isolated HILDCAAs (~60%). Possible physical interpretations for the statistical results obtained in this paper are discussed.

Bow shock: Power aspects

It is clear that the primary energy source for magnetospheric processes is the solar wind, but the process of energy transfer from the solar wind into the magnetosphere, or rather, to convecting magnetospheric plasma, appears to be rather complicated. Bow shock is a powerful transformer of the solar wind kinetic energy into the gas dynamic and electromagnetic energy. A jump of the magnetic field tangential component at front crossing means that the front carries an electric current. The solar wind kinetic energy partly transforms to gas kinetic and electromagnetic energy during its passage through the bow shock front. The transition layer (magnetosheath) can use part of this energy for accelerating of plasma, but can conversely spend part its kinetic energy on the electric power generation, which afterwards may be used by the magnetosphere. Thereby, transition layer can be both consumer (sink) and generator (source) of electric power depending upon special conditions. The direction of the current behind the bow shock front depends on the sign of the IMF Bz-component. It is this electric current which sets convection of plasma in motion.

On nonlinear cascades and resonances in the outer magnetosphere

The paper addresses nonlinear phenomena that control the interaction between plasma flow (solar wind) and magnetic barrier (magnetosphere). For the first time we demonstrate that the dominant solar wind kinetic energy: (i) excites boundary resonances and their harmonics which modulate plasma jets under the bow shock; (ii) produces discrete three-wave cascades, which could merge into a turbulent-like one; (iii) jet produced cascades provide the effective anomalous plasma transport inside and out of the magnetosphere; (iv) intermittency and multifractality characteristics for the statistic properties of jets result in a super-ballistic turbulent transport regime. Our results could be considered as suggestive for the space weather predictions, for turbulent cascades in different media and for the laboratory plasma confinement (e.g., for fusion devices).

Enhanced atmospheric oxygen outflow on Earth and Mars driven by a corotating interaction region

Solar wind controls nonthermal escape of planetary atmospheric volatiles, regardless of the strength of planetary magnetic fields. For both Earth with a strong dipole and Mars with weak remnant fields, the oxygen ion (O+) outflow has been separately found to be enhanced during corotating interaction region (CIR) passage. Here we compared the enhancements of O+ outflow on Earth and Mars driven by a CIR in January 2008, when Sun, Earth, and Mars were approximately aligned. The CIR propagation was recorded by STEREO, ACE, Cluster, and Mars Express (MEX). During the CIR passage, Cluster observed enhanced flux of upwelling oxygen ions above the Earth's polar region, while MEX detected an increased escape flux of oxygen ions in the Martian magnetosphere. We found that (1) under a solar wind dynamic pressure increase of 2–3 nPa, the rate of increase in Martian O+ outflow flux was 1 order higher than those on Earth; and (2) as a response to the same part of the CIR body, the rate of increase in Martian O+ outflow flux was on the same order as for Earth. The comparison results imply that the dipole effectively prevents coupling of solar wind kinetic energy to planetary ions, and the distance to the Sun is also crucially important for planetary volatile loss in our inner solar system.

Magnetospheric feedback in solar wind energy transfer

The solar wind kinetic energy fueling all dynamical processes within the near‐Earth space is extracted in a dynamo process at the magnetopause. This direct energy transfer from the solar wind into the magnetosphere depends on the orientation of the interplanetary magnetic field (IMF) as well as other solar wind parameters, such as the IMF magnitude and solar wind velocity. Using the GUMICS‐4 magnetohydrodynamic (MHD) simulation, we find that the energy input from the solar wind into the magnetosphere depends on this direct driving as well as the magnetopause magnetic properties and their time history in such a way that the energy transfer can continue even after the direct driving conditions turned unfavorable. Such a hysteresis effect introduces discrepancies between the energy input proxies and the energy input measured from GUMICS‐4, especially after strong driving, although otherwise the simulation energy input captures the system dynamics. For the cause of the effect, we propose a simple feedback mechanism based on magnetic flux accumulation in the tail lobes. By ideal MHD theory, the energy conversion at the magnetopause is proportional to the product of normal and tangential magnetic fields, the magnetic stress. During large magnetic flux accumulation, the tangential field at the magnetopause strengthens, enhancing the local instantaneous energy conversion and transfer. Our simulations show that this mechanism supports the energy transfer even under weak driving followed by favorable solar wind conditions and transfer up to 50% more power than without the feedback.

How can we solve the problem of substorms? (A review)

The works in the alternative direction of magnetospheric studies are reviewed. In contrast to the traditional approach, where the basis process is magnetic field line reconnection, transformation of kinetic energy into electromagnetic one at the bow shock front is the basis process in the proposed approach. It has been indicated that this new paradigm makes it possible to overcome the main difficulties that remained within the scope of the previous paradigm. It has been briefly demonstrated how several following processes and phenomena are explained within the scope of the new approach: (1) transformation of the solar wind kinetic energy into the electromagnetic energy; (2) electromagnetic energy transfer into the magnetosphere; (3) organization of the system of bulk currents, formation of field-aligned currents from the magnetosphere, and compatibility of these currents with the ionospheric current systems; (4) shape, value, and dynamics of the particle precipitation auroral regions; and (5) substorm expansion (auroral breakup). Other possibilities of the new approach and paradigm replacement consequences are briefly considered.

Some characteristics of intense geomagnetic storms and their energy budget

The present study analyses nine intense geomagnetic storms (∣Dst∣ > 175 nT) with the aid of ACE satellite measurements and ground magnetic field values at Alibag Magnetic Observatory. The study confirms the crucial role of southward IMF in triggering the storm main phase as well as controlling the magnitude of the storm. The main phase interval shows clear dependence on the duration of southward IMF. An attempt is made to identify the multipeak signature in the ring current energy injection rate during main phase of the storm. In order to quantify the energy budget of magnetic storms, the present paper computes the solar wind energies, magnetospheric coupling energies, auroral and Joule heating energies, and the ring current energies for each storm under examination. Computation of the solar wind‐ magnetosphere coupling function considers the variation of the size of the magnetosphere by using the measured solar wind ram pressure. During the main phase of the storm, the solar wind kinetic energy ranges from 9 × 1017 to 72 × 1017 J with an average of 30 × 1017 J; the total energy dissipated in the auroral ionosphere varies between 2 × 1015 and 9 × 1015 J, whereas ring current energies range from 8 × 1015 to 19 × 1015 J. For the total storm period, about 3.5% of total solar wind kinetic energy is available for the redistribution in the magnetosphere, and around 20% of this goes into the inner magnetosphere and in the auroral ionosphere of both the hemispheres. It is found that during main phase of the storm, almost 5% of the total solar wind kinetic energy is available for the redistribution in the magnetosphere, whereas during the recovery phase the percentage becomes 2.3%.

From the Solar Wind to the Magnetospheric Substorm

This paper gives a brief outline of the progression from the first substorm model developed in Ref.[4] and<br>[8] based on Kennel's ideas[3], to the present views about the mechanism by which solar wind kinetic energy is converted to electromagnetic energy at the Bow Shock and by which this energy is transferred to the magnetosphere in the form of current; about the transformation of the energy of this current to gas kinetic energy of convecting plasma tubes, and, finally, the back transformation of gas kinetic energy to electromagnetic energy in secondary magnetospheric MHD generators. The questions of the formation of the magnetospheric convection system, the nature of substorm break-up, and of the matching of currents in the magnetosphere-ionosphere system are discussed.

Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

Abstract. We make a statistical study of ionospheric Joule heating with the Poynting flux method using six months of Astrid-2/EMMA electric and magnetic field data during 1999 (solar maximum year). For the background magnetic field we use the IGRF model. Our results are in agreement with earlier statistical satellite studies using both the ΣPE2 method and the Poynting flux method. We present a rather comprehensive set of fitted Joule heating formulas expressing the Joule heating in given magnetic local time (MLT) and invariant latitude (ILAT) range under given solar illumination conditions as a function of the Kp index, the AE index, the Akasofu epsilon parameter and the solar wind kinetic energy flux. The study thus provides improved and more detailed estimates of the statistical Joule heating. Such estimates are necessary building blocks for future quantitative studies of the power budget in the magnetosphere and in the nightside auroral region. Key words. Ionosphere (electric fields and currents; ionosphere-magnetosphere interactions) – Magnetospheric physics (magnetospheric configuration and dynamics)