Thermal Radiation Force Research Articles

Thermal radiation forces on planar structures with asymmetric optical response

Abstract Light carries momentum and, upon interaction with material structures, can exert forces on them. Here, we show that a planar structure with asymmetric optical response is spontaneously accelerated when placed in an environment at a different temperature. This phenomenon originates from the imbalance in the exchange rates of photons between both sides of the structure and the environment. Using a simple theoretical model, we calculate the force acting on the planar structure and its terminal velocity in vacuum, and analyze their dependence on the initial temperature and the geometrical properties of the system for different realistic materials. Our results unravel an alternative approach to manipulating objects in the nano and microscale that does not require an external source of radiation.

Measurement of Near-Field Radiative Heat Transfer at Deep Sub-Wavelength Distances using Nanomechanical Resonators.

Near-field radiative heat transfer (NFRHT) measurements often rely on custom microdevices that can be difficult to reproduce after their original demonstration. Here we study NFRHT using plain silicon nitride (SiN) membrane nanomechanical resonators─a widely available substrate used in applications such as electron microscopy and optomechanics─and on which other materials can easily be deposited. We report measurements down to a minimal distance of 180 nm between a large radius of curvature (15.5 mm) glass radiator and a SiN membrane resonator. At such deep sub-wavelength distance, heat transfer is dominated by surface polariton resonances over a (0.25 mm)2 effective area, which is comparable to plane-plane experiments employing custom microfabricated devices. We also discuss how measurements using nanomechanical resonators create opportunities for simultaneously measuring near-field radiative heat transfer and thermal radiation forces (e.g., thermal corrections to Casimir forces).

Estimating surface optical properties and thermal thrust for Galileo satellite body and solar panels

Precise orbit determination of GNSS (Global Navigation Satellite System) satellites requires accurate models of perturbing forces acting on the spacecraft, i.e., solar radiation pressure (SRP) and thermal radiation forces. With the officially published satellite metadata, the analytical box-wing model is usually used to describe most of the SRP accelerations and the rest is assumed to be compensated by estimating ECOM/ECOM2 (Empirical CODE Orbit Model) parameters. However, we find that the precision of Galileo satellite orbits shows notable degradation inside eclipse seasons for 3-day-arc solutions and 24-h predictions. For instance, the RMS (root-mean-square) of orbit misclosures increases by about a factor of two in the eclipse season when using the box-wing model as the a priori and the 5-parameter ECOM model on top. The reason is proven to be mostly due to ignoring imbalanced thermal radiation forces (i.e., radiator emission and thermal radiation of solar panels) as satellite thermal properties are unknown. These imbalanced thermal effects cannot be fully absorbed by the ECOM/ECOM2 parameters inside eclipse seasons because the earth’s shadowing of a satellite in orbit causes periodic changes of the thermal environment. To cope with this problem, we first estimate satellite optical and thermal parameters as part of orbit determination based on Galileo tracking data covering 1 year. Then, we add physical thermal radiation models for radiators and solar panels as part of the a priori model and evaluate the performance of different ECOM models in Galileo satellite orbit determination. As shown by orbit misclosures, 24-h orbit predictions and SLR (Satellite Laser Ranging) residuals, the 7-parameter ECOM2 model performs better than the 5-parameter ECOM and the 9-parameter ECOM2 model for Galileo satellites. When using the 7-parameter ECOM2 model on top, the impact of the radiator emission and the thermal radiation of solar panels on Galileo satellite orbits is about 1 and 2 cm, respectively, inside eclipse seasons for 3-day-arc solutions.

Ephemeris and hazard assessment for near-Earth asteroid (101955) Bennu based on OSIRIS-REx data

Small bodies such as the near-Earth asteroid Bennu drift in their orbit due to thermal radiation forces (the Yarkovsky effect). Ground-based observations have indicated a nonzero probability of Bennu impacting Earth, depending on how its orbit evolves. Thus, among the goals of the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission to Bennu were to precisely measure the Yarkovsky effect and refine the impact hazard assessment for this body. Here we address these objectives. Using OSIRIS-REx spacecraft tracking data, we derive meter-level constraints on the distance between Earth and Bennu from January 2019 to October 2020. While these data greatly improve the knowledge of the trajectory of Bennu, they also require an unprecedented fidelity for the modeling of an asteroid’s trajectory. In particular, special care is needed to take into account the contribution of 343 small-body perturbers and the uncertainty in their masses. Radiation effects such as the Poynting–Robertson drag, so far only considered for interplanetary dust dynamics, now become a consideration for modeling the trajectory of a 500-m asteroid such as Bennu. By employing a thermophysical model based on OSIRIS-REx’s characterization of Bennu, we estimate a semimajor axis drift of −284.6±0.2 m/yr (signal-to-noise ratio ∼1400) at epoch 2011 January 1 caused by the Yarkovsky effect. The largest source of modeling error is solar wind drag, which may lower the magnitude of the semimajor axis drift from the Yarkovsky effect by up to 0.16 m/yr. The Yarkovsky-related semimajor axis drift varies by roughly ±1 m/yr as the orbit of Bennu evolves due to planetary perturbations from 1900 to 2135. The Yarkovsky thermophysical model proves to be extremely accurate by predicting a bulk density estimate within 0.1% of that estimated through gravity science analysis. Compared to the information available before the OSIRIS-REx mission, the knowledge of the circumstances of the scattering Earth encounter that will occur in 2135 improves by a factor of 20, thus allowing us to rule out many previously possible impact trajectories. However, there remain some impact trajectories compatible with the data. Prior to the spacecraft encounter, the overall impact probability through 2200 was 3.7×10−4 (1 in 2700). As a result of our analysis, the cumulative impact probability through 2300 becomes 5.7×10−4 (1 in 1750) and the most significant individual impact solution is for September 2182, with an impact probability of 3.7×10−4 (1 in 2700). Both Bennu and (29075) 1950 DA have a Palermo scale value of −1.42 and share the distinction as the currently most hazardous object in the asteroid catalog.

EARLINET observations of Saharan dust intrusions over the northern Mediterranean region (2014–2017): properties and impact on radiative forcing

Abstract. Remote sensing measurements of aerosols using depolarization Raman lidar systems from four EARLINET (European Aerosol Research Lidar Network) stations are used for a comprehensive analysis of Saharan dust events over the Mediterranean basin in the period 2014–2017. In this period, 51 dust events regarding the geometrical, optical and microphysical properties of dust were selected, classified and assessed according to their radiative forcing effect on the atmosphere. From west to east, the stations of Granada, Potenza, Athens and Limassol were selected as representative Mediterranean cities regularly affected by Saharan dust intrusions. Emphasis was given on lidar measurements in the visible (532 nm) and specifically on the consistency of the particle linear depolarization ratio (δp532), the extinction-to-backscatter lidar ratio (LR532) and the aerosol optical thickness (AOT532) within the observed dust layers. We found mean δp532 values of 0.24±0.05, 0.26±0.06, 0.28±0.05 and 0.28±0.04, mean LR532 values of 52±8, 51±9, 52±9 and 49±6 sr and mean AOT532 values of 0.40±0.31, 0.11±0.07, 0.12±0.10 and 0.32±0.17, for Granada, Potenza, Athens and Limassol, respectively. The mean layer thickness values were found to range from ∼ 1700 to ∼ 3400 m a.s.l. Additionally, based also on a previous aerosol type classification scheme provided by airborne High Spectral Resolution Lidar (HSRL) observations and on air mass backward trajectory analysis, a clustering analysis was performed in order to identify the mixing state of the dusty layers over the studied area. Furthermore, a synergy of lidar measurements and modeling was used to analyze the solar and thermal radiative forcing of airborne dust in detail. In total, a cooling behavior in the solar range and a significantly lower heating behavior in the thermal range was estimated. Depending on the dust optical and geometrical properties, the load intensity and the solar zenith angle (SZA), the estimated solar radiative forcing values range from −59 to −22 W m−2 at the surface and from −24 to −1 W m−2 at the top of the atmosphere (TOA). Similarly, in the thermal spectral range these values range from +2 to +4 W m−2 for the surface and from +1 to +3 W m−2 for the TOA. Finally, the radiative forcing seems to be inversely proportional to the dust mixing ratio, since higher absolute values are estimated for less mixed dust layers.

Yarkovsky Effect on the Orbital Dynamics of 1566 Icarus Asteroid

The orbital dynamic of small objects is an n-body problem that can not be solve by analitically, it is needed to use numerical integration to find the solution instead. This work is about orbital dynamic of asteroid 1566 Icarus under Classical Newtonian gravitation and if thermal effect (Yarkovsky effect) is included. Yarkovsky Effect is a thermal radiation force resulted from time span of small rotating objects to receive heat from the Sun and then re-radiates it. The Yarkovsky Effect is working optimum for objects with diameter from 10 cm up to 10 km, and now is implemented to Asteroid 1566 Icarus with diameter 1.3 km which are member of Apollo and Earth crosser object. This Asteroid is called Earth crosser due to its orbit is crossing Earth’s orbit. With semi major axis a  1.078 au and eccentricity e  0.827, asteroid 1566 Icarus has perihelion distance q = 0.18674 au or less than semi major axis of Mercury. Due to that reason, Yarkovsky effect was considered to be applied on the orbital dynamics of asteroid 1566 Icarus. Due to sensitivity in input-data of numerical integration for n-body, one hundred simulation preliminary data were made as input in numerical integration process, therefore, 100 clones of Asteroid 1566 Icarus are gathered. Cloning process was conducted by using random number from Asteroid 1566 Icarus orbital elements at epoch 2456800.5 (23 May 2014) to standard deviation . The integration then later conducted within 105 years time span from the epoch. The result shown that the orbital dynamics of asteroid 1566 Icarus with Yarkovsky effect is still within the range of 100 clones of asteroid 1566 Icarus. Thereby, within 105 years, Yarkovsky effect does not change the orbital dynamic of asteroid 1566 Icarus globally, except for two phenomenon between close encounter with planet.

DETECTION OF THE YORP EFFECT FOR SMALL ASTEROIDS IN THE KARIN CLUSTER

ABSTRACT The Karin cluster is a young asteroid family thought to have formed only ≃ 5.75 Myr ago. The young age can be demonstrated by numerically integrating the orbits of Karin cluster members backward in time and showing the convergence of the perihelion and nodal longitudes (as well as other orbital elements). Previous work has pointed out that the convergence is not ideal if the backward integration only accounts for the gravitational perturbations from the solar system planets. It improves when the thermal radiation force known as the Yarkovsky effect is accounted for. This argument can be used to estimate the spin obliquities of the Karin cluster members. Here we take advantage of the fast growing membership of the Karin cluster and show that the obliquity distribution of diameter D ≃ 1 – 2 km Karin asteroids is bimodal, as expected if the YORP effect acted to move obliquities toward extreme values (0° or 180°). The measured magnitude of the effect is consistent with the standard YORP model. The surface thermal conductivity is inferred to be 0.07–0.2 W m−1 K−1 (thermal inertia ≃ 300 – 500 J m−2 K−1 s − 1 / 2 ). We find that the strength of the YORP effect is roughly ≃ 0.7 of the nominal strength obtained for a collection of random Gaussian spheroids. These results are consistent with a surface composed of rough, rocky regolith. The obliquity values predicted here for 480 members of the Karin cluster can be validated by the light-curve inversion method.

On the irreversible thermodynamic of a gas influenced by a thermal radiation force generated from a heated rigid flat plate

In the present paper, the effect of the nonlinear thermal radiation (TR) on the neutral gas mixture in the unsteady state is investigated for the first time. The unsteady BGK technique of the Boltzmann kinetic equation (BKE) for a non-homogenous neutral gas (NHNG) is solved. The solution of the unsteady case makes the problem more general than the stationary case. For this purpose, the moments’ method, together with the traveling wave method, is applied. The temperature and concentration are calculated for each gas component and mixture for the first time. Furthermore, the study is held for aboard range of temperatures ratio parameter and a wide range of the molar fraction. The non-equilibrium distribution function (NEDF) is calculated for each gas component and the gas mixture. The significant non-equilibrium irreversible thermodynamic characteristics the entire system is acquired analytically. That technic allows us to investigate our model consistency with Boltzmann’s H-theorem, Le Chatelier’s principle, and thermodynamics laws. Moreover, the ratios among the further participation of the internal energy change (IEC) are evaluated via the Gibbs formula of total energy. The final results are utilized to the argon-helium NHNG at different magnitudes of radiation force (RF) strength and molar fraction parameters. 3D-graphics are presented to predict the behavior of the calculated variables, and the obtained results are theoretically discussed. The significance of this study is due to its vast applications in numerous fields, such as satellites, commercial, and various industrial applications.

THE YARKOVSKY AND YORP EFFECTS: Implications for Asteroid Dynamics

The Yarkovsky and YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effects are thermal radiation forces and torques that cause small objects to undergo semimajor axis drift and spin vector modifications, respectively, as a function of their spin, orbit, and material properties. These mechanisms help to (a) deliver asteroids (and meteoroids) with diameter D < 40 km from their source locations in the main belt to chaotic resonance zones capable of transporting this material to Earth-crossing orbits; (b) disperse asteroid families, with drifting bodies jumping or becoming trapped in mean-motion and secular resonances within the main belt; (c) modify the rotation rates and obliquities of D < 40 km asteroids; and (d) allow asteroids to enter into spin-orbit resonances, which affect the evolution of their spin vectors and feedback into the Yarkovsky-driven semimajor axis evolution. Accordingly, we suggest that nongravitational forces should now be considered as important as collisions and gravitational perturbations to our overall understanding of asteroid evolution.

Direct thermal radiative forcing of tropospheric aerosol in the Arctic measured by ground based infrared spectrometry

We present, to our knowledge for the first time in the high Arctic, atmospheric thermal emission spectra recorded by ground‐based FTIR spectrometry revealing an excess emission contribution, which can only be attributed to the presence of tropospheric aerosols. Consideration of direct thermal forcing in climatological sensitive and remote regions as the Arctic seems to be important for more realistic modelling. According to our measurements, the aerosols can alter the flux density of downward longwave radiation by up to +2.99 to +4.66 W m−2, and the flux density of outgoing longwave radiation by −0.23 to +1.17 W m−2.

Spin axis behavior of the LAGEOS satellites

The satellites LAGEOS‐I and LAGEOS‐II are essential for the scientific study of various (geo)physical phenomena, such as geocenter motion and absolute scale. The high quality of such science products strongly depends on the absolute quality of the SLR observations and that of the orbit description. Therefore all accelerations experienced by the spacecraft need to be modeled as accurately as possible, the thermal radiation forces being one of them. Traditionally, this is done by estimating so‐called empirical accelerations. However, the rotational dynamics of LAGEOS‐I in particular no longer allows such a simple approach: a full modeling of the spin behavior, the temperature distribution over the spacecraft surface and the resulting net force prove necessary to achieve the best results. As a first step, a new model, Lageos Spin Axis Model (LOSSAM) has been developed. It is unique in its combination of analytical theory and empirical observations. Its mathematics is taken after previous investigators, although flaws have been corrected. LOSSAM describes the full spin behavior of LOSSAM based on the following phenomena: (1) the geomagnetic field, (2) the Earth's gravity field, (3) the satellite center of pressure offset, and (4) the effective difference in reflectivity between the satellite hemispheres. Its accuracy has been demonstrated by an improvement of about a 50% in the RMS residual of the Yarkovsky‐Schach effect signal (as shown by Lucchesi et al. [2004]). Such a high‐quality model for rotational behavior is indispensable for a proper force modeling, and hence also for the quality of typical LAGEOS science products.

A naive accelerometer acting in the continuum range.

The space experiment TRAMP (Thermal Radiation Aspects of Migrating Particles) flown in 1999 onboard the mission Foton 12 sponsored by the European Space Agency (ESA), was conceived to reveal and measure a new kind of forces, named Thermal Radiation Forces (TRF). The experiment was dramatically disturbed by the occurrence of undesired convective motions due to the rotation of the spacecraft. Apart from that, corrosion occurred in some parts of the flight apparatus, resulting in the presence of gas bubbles inside the experimental liquid, completely compromising the results. Consequently, the experiment did not allow to reveal and/or to measure TRF, but it turned out to be useful in another way, as a very sensitive accelerometer, since the accelerations deduced from velocity measurements concurred with those measured by the Quasi-Steady Acceleration Measurement (QSAM) system.

Properties of coastal Antarctic aerosol from combined FTIR spectrometer and sun photometer measurements

Remotely sensing the physical and chemical properties of summertime aerosol at the Antarctic coastal station Neumayer has been accomplished for the first time by a combined analysis of atmospheric thermal emission spectra, measured by an FTIR spectrometer, and atmospheric visible‐near infrared extinction spectra, measured by a sun photometer. From the synergy of both spectral ranges, we find that the aerosol is composed of 1.1–1.6 mg m−2 of sulfates, with the water component in the solid phase, having a bimodal size distribution with radii peaking at 0.04 and 0.64 μm. We also provide the first estimate of the direct thermal radiative forcing of this aerosol: +1.68 W m−2 at the surface, and +0.006 W m−2 at the top of the atmosphere.

The Depletion of the Putative Vulcanoid Population via the Yarkovsky Effect

The geophysical history of Mercury is constrained by its crater record, its tectonics, and its magnetic field. Standard thermal models based on these constraints lead to inconsistent results unless Mercury was bombarded in its early history by an additional population of impactors. It has been suggested that the putative vulcanoid population, a belt of asteroid-like bodies residing on stable orbits inside the orbit of Mercury, may be the source of these impactors. Previous work has shown that collisions among vulcanoids are sufficient to deplete the stable vulcanoid zone of most multikilometer bodies within a billion years or so. In this paper, we examine whether the Yarkovsky effect, a thermal radiation force which forces asteroids to undergo semimajor axis drift as a function of their spin, orbit, and material properties, is strong enough to deplete the remaining material from the vulcanoid zone. Our results show that most kilometer-sized bodies escape into unstable orbits within a few billion years. We predict that the contemporary vulcanoid population, if it exists at all, may be limited to 300–900 bodies larger than 1 km in diameter.

Experimental Detection of Forces Produced by the Flow of Heat

We detected thermal radiation forces produced by heat flow through solid slabs suspended in nonisothermal liquids. Lateral effects are avoided, allowing a unidimensional approach. The results confirm expectations. Numerically simulated gravity-dependent perturbations are smaller than the measured forces. More precise measurements will be attempted on a European Space Agency suborbital flight in 1998.

General Circulation Model Calculations of the Direct Radiative Forcing by Anthropogenic Sulfate and Fossil-Fuel Soot Aerosol

Abstract A new radiation code within a general circulation model is used to assess the direct solar and thermal radiative forcing by sulfate aerosol of anthropogenic origin and soot aerosol from fossil-fuel burning. The radiative effects of different aerosol profiles, relative humidity parameterizations, chemical compositions, and internal and external mixtures of the two aerosol types are investigated. The contribution to the radiative forcing from cloudy sky regions is found to be negligible for sulfate aerosol; this is in contrast to recent studies where the cloudy sky contribution was estimated using a method in which the spatial correlation between cloud amount and sulfate burden was ignored. However, the radiative forcing due to fossil-fuel soot aerosol is enhanced in cloudy regions if soot aerosol exists within or above the cloud. The global solar radiative forcing due to sulfate aerosol is estimated to be −0.38 W m−2 and the global thermal radiative forcing is estimated to be +0.01 W m−2. The hemi...

Phonons in liquids, Onsager's reciprocal relations, and the heats of transport.

We continue the study of liquids considered as composed by two interacting subsystems: a population of particles, weakly bound to the sites of a disordered lattice, and a ``gas'' of phonons. The interactions among the material particles and the wave packets are mediated by ``thermal radiation forces,'' a special class of inertial effects. When the liquid system is a solution, the application of a temperature or a concentration gradient breaks the symmetry of one of the two subsystems, producing an excess of phonon-solute collisions and performing work on the particles, at the expense of the thermal energy of the wave packets. The heats of transport of thermal diffusion, isothermal diffusion, and Soret equilibrium may be statistically calculated from the energy balance of these collisions. The expressions arrived at by this approach are coincident with the ones obtained by nonequilibrium thermodynamics, although for our derivation Onsager reciprocal relations are not required. It is also argued that, within the frame of the phonon theory, transport processes in liquids may be treated in general by means of the classical Boltzmann transport equation, applied to phonon-particle interactions rather than to particle-particle collisions.

Phonon-particle interactions and transport processes in liquids.

The theory of thermal radiation forces is extended to the local interactions occurring among phonons and the material particles of a liquid, also in the absence of an external temperature gradient. In a solution, energy and momentum can be transferred by an impinging phonon to a particle, or the latter may perform work on the first, shifting it to a higher frequency. Upon time reversal, each of these elementary interactions commutes into the other. Isothermal diffusion, thermomechanical and mechanothermal effects in solutions can be interpreted within this unifying frame of reference. The density of the ``gas'' of thermal excitations, and the average of energy exchanged per interaction can be calculated from experimental data for common liquids. Nonequilibrium statistical mechanics and irreversible thermodynamics might be fruitfully revisited on the basis of the notion of phonon-particle interactions, since these are processes that occur at a more elementary level than the regression of fluctuations. Accordingly, the statistical approach proposed here may lead to a microscopic interpretation of Onsager's reciprocity relations.

Radiation forces associated with heat propagation in nonisothermal systems.

The aim of this work is to show that, in the condensed phases, the flux of thermal energy couples with a flux of momentum. This follows from considerations of rational mechanics and can be also deduced as a corollary of a theorem established by Boltzmann, following a straightforward reasoning already developed by Ehrenfest in a somewhat simpler case than the one considered by us. When heat flux crosses the boundary between two adjoining media, the momentum flux changes, and ``thermal radiation forces'' should appear. Accordingly, the momentum-balance equation of continuous-field hydrodynamics should include, when applied to nonisothermal media, the momentum flux due to heat flow. When this is done, analytical expressions for thermal radiation forces are obtained with reference to various simple physical systems. The theoretical predictions lend themselves to direct experimental verification. Very good qualitative and quantitative agreement between theory and experiment has been found in various experimental systems, as described here, lending strong support to the proposed approach. Interestingly, experimental results obtained with macroscopic objects and with molecular or ionic particles both lead to analogous conclusions concerning the properties of thermal radiation forces, a circumstance that broadens the possible field of application of these concepts. Finally, it is suggested that the concept of momentum flux coupled to transport of thermal energy in the condensed phases can be fruitfully employed in the investigation of complex phenomena such as acoustic streaming and the B\'ernard-Rayleigh instabilities.