Radiation Pressure Force Research Articles

Continuous Space-Time Crystal State Driven by Nonreciprocal Optical Forces.

We show that the continuous time crystal state can arise in an ensemble of linear oscillators from nonconservative coupling via optical radiation pressure forces. This new mechanism comprehensively explains observations of the time crystal state in an array of nanowires illuminated with light [T. Liu et al., Nat. Phys. 19, 986 (2023).NPAHAX1745-247310.1038/s41567-023-02023-5]. Being fundamentally different from regimes of nonlinear synchronization, it has relevance to a wide range of interacting many-body systems, including in the realms of chemistry, biology, weather, and nanoscale matter.

Optical manipulations without light forces: deep superlattice for trapping and rotation of impurity particles in a buffer gas

We propose a scheme to obtain a deep optical superlattice (OSL) for resonant impurity particles in a buffer gas. In contrast to the well-known traditional methods of forming optical lattices (supelattices) that are based on the gradient force of radiation pressure, the presented scheme is based on the effect of a light induced drift (LID) in interfering light waves. The principle of its operation is based on the conception of so-called rectified forces induced by interfering bichromatic optical fields, which was developed earlier in the theory of resonant radiation-pressure forces. In the scheme under consideration, a deep OSL (with a period much larger than the optical wavelength) is formed due to the action of the effective rectified force on atomic particles which is proportional to the difference between the frequencies of transport collisions of excited and unexcited particles with buffer gas atoms.

Dynamics and control for spacecraft tracking a displaced orbit around an asteroid exploiting solar sail

This study investigates the displaced orbit around a near-Earth asteroid for spacecraft achieved via a realistic solar sail with a performance based on the existing technology in a low distance. Using the realistic solar sail to achieve the displaced orbit with a short displaced distance is more difficult compared with using a traditional thruster under two main limitations: The force limitation and the position limitation. Firstly, the solar radiation pressure (SRP) force generated by the solar sail is limited by the solar sail’s property and the sunlight direction. Therefore, the feasibility of maintaining a displaced orbit at an equilibrium point around the asteroid at a low distance using a solar sail with realistic performance is investigated analytically. The results demonstrate that the equilibrium point of the displaced orbit can be achieved. Secondly, the usage of the solar sail is also limited by the position of the spacecraft. The SRP force cannot be generated in the eclipse region wherein sunlight is absent; specifically, in a displaced orbit with a low displaced distance, the position limitation is more notable. To address this challenge, spacecraft dynamics and control using a solar sail are investigated to achieve the displaced orbit, and a method of orbit transfer outside the eclipse region is proposed. Numerical simulations reveal that the spacecraft can maintain the displaced orbit using the solar sail without entering the eclipse region. Moreover, spacecraft can achieve orbit transfer between two equilibrium points without entering the eclipse region by using the solar sail. The impact of non-spherical shape of the primary asteroid is also investigated. Results show that the proposed method can maintain a displaced orbit with errors from the reference state less than 10 % during a limited time span when the primary asteroid has a non-spherical shape.

Chaotic libration and control of a space tether-sail system in Earth polar orbits with J2 perturbation

The recently proposed space tether-sail system could enable various interesting and important potential space missions thanks to its thin and long connecting tether and solar radiation pressure (SRP) force without consuming propellants. This paper focuses on nonlinear libration and its control of a tether-sail system in Earth polar orbits. Firstly, nonlinear coupled in-plane and out-of-plane dynamics of the system with a rigid mass-distributed tether and two point masses (a chief satellite and sail respectively) is established using the Lagrangian equation method. Secondly, the predicted occurrence of chaotic in- and out-of-plane librational motions is verified utilizing numerical tools such as presenting the time history of libration, the phase plane, the Poincaré section and power spectral density(PSD). Specifically, the paper investigates the sensitivity of nonlinear dynamical responses to initial values, focuses on the chaotic motion caused by the coupling between the in- and out-of-plane librations, the J2 perturbation of the Earth gravitational field and the small eccentricity of the orbits, also studies the nonlinear librational characteristics influenced by the initial mechanical energy (the Hamiltonian). Thirdly, chaotic librational motions will be controlled merely using modulatable SRP force by the sail propellantlessly. A sliding mode controller based on exponential approaching law is developed. To mitigate the effects of control torque saturation, an input compensator based on Radial Basis Function (RBF) neural network is designed. In addition, to address the cumbersome and inefficient manual tuning of control parameters for the sliding mode controller, a parameter tuning algorithm based on Learning Automata is designed. This algorithm is capable of tuning a high-quality set of controller parameters within 100 iterations. The effectiveness of the propellantless actuators for chaotic libration motion control and developed control algorithm is supported by numerical simulations.

Effect of the solar radiation pressure on the motion of satellites in almost circular Earth orbits

This paper considers the effect of the solar radiation pressure on the motion of a satellite in an almostcircular low-Earth orbit. The formulation of the problem is due to the need to determine the effect of solar radiation pressure forces on the motion of light commercial Earth remote sensing (ERS) satellites with large surface areas (solar batteries and antennas). The goal is to determine the main regularities of this effect, construct reasonably simple and accurate estimates of changes in orbital parameters for the orbits under consideration, and clarify their physics (cause-and-effect relations) The novelty of this study also lies in the use of variables specially introduced to describe a motion in almost circular orbits. The study assumes that the solar radiation pressure force is constant throughout the entire orbit, and it is concerned with dawn-dusk orbits, which are often used for ERS satellites with radar observation systems. The paper presents simple analytical expressions that describe the main regularities of short-term (several days) changes in orbital parameters. It is shown that the change in the orientation of the orbital plane is determined by the action of the gyroscopic moment. This moment balances the effect of the moment of external forces aimed at changing the orientation and the change in the orientation perpendicular to the direction of the applied moment of the external forces. The main effect of the solar radiation pressure is the excitation of forced oscillations of the orbital radius, whose amplitude linearly increases with time. The maximums of these oscillations (apogee) are at the point where the light pressure forces maximally slow down the motion of the satellite (directed oppositely to the velocity), and the minimums (perigee) are at the point of the maximum motion acceleration. It is shown that the annual movement of the Sun can qualitatively change the picture of the evolution of orbital parameters. For sun-synchronous dawn-dusk orbits, compact analytical solutions for changes in orbital parameters are constructed, and it is shown that the annual movement of the Sun’s declination reverses the direction of evolution of the orbital shape. The calculations showed a reasonably high accuracy of the analytical solutions at the initial stage. The obtained numerical estimates make it possible to evaluate the effect of the solar pressure on changes in orbital parameters.

Inner dusty regions of protoplanetary discs – III. The role of non-radial radiation pressure in dust dynamics

ABSTRACT We explore the dynamical behaviour of dust particles that populate the surface of inner optically thick protoplanetary discs. This is a disc region with the hottest dust and is of a great importance for planet formation and dust evolution, but we still struggle to understand all the forces that shape this environment. In our approach, we combine results from two separate numerical studies, one is the wind velocity and density distributions obtained from magnetohydrodynamical simulations of accretion discs, and the other is a high-resolution multigrain dust radiation transfer. In our previous paper in the series, we described the methodology for utilizing these results as an environmental input for the integration of dust trajectories driven by gravity, gas drag, and radiation pressure. Now we have two improvements, we incorporate time changes in the wind density and velocity, and we implement the non-radial radiation pressure force. We applied our analysis on the Herbig Ae and T Tau stars. We confirm that the radiation pressure force can lead to dust outflow, especially in the case of more luminous stars. Additionally, it opposes dust accretion at the inner disc edge and reduces dust settling. These effects are enhanced by the disc wind, especially in the zone where the stellar and the disc magnetic fields meet. Our results suggest that dust grains can stay in the hottest disc region for an extended period and then end up ejected into the outer disc regions.

Effects of an Explicit Time-dependent Radiation Pressure Force on Trajectories of Primary Neutral Hydrogen in the Heliosphere

Radiation pressure exerted by solar photon output is salient to the motion of primary neutral hydrogen atoms streaming into the inner heliosphere directly from the local interstellar medium. The action of a time-dependent radiation pressure force, when coupled with the usual gravitational force, changes the characteristic velocities, and therefore energies, of the atoms when they reach regions in which explorer probes are present. A study is presented that uses a 2D code to backtrace neutral hydrogen trajectories from representative target points located 1 au from the Sun. It makes use of both a radiation pressure function and a function for the photoionization rate at 1 au that both oscillate with time based on measurements over a typical solar cycle, as well as a time-independent charge exchange ionization rate at 1 au. Assuming a Maxwellian distribution in the distant upwind direction, phase space data is calculated at the target points, at different moments in time. The dependence of the force on the radial particle velocity has been omitted in the analysis, such that the emphasis is on the effects of the global solar UV intensity variations through the solar cycle. This process allows for the analysis of direct and indirect Maxwellian components through time and space in the time-dependent force environment. Additionally, pseudo-bound orbits caused by energy losses associated with this force environment are observed, and their properties are evaluated with the aim of determining their effects on potential measurements by explorer probes.

Extension of optical radiation pressure force exerted on rigid sphere by non-diffracting beams to acoustical domain

Extension of optical radiation pressure force exerted on rigid sphere by non-diffracting beams to acoustical domain

Optical Nonreciprocity in a Multimode Cavity Optomechanical System Controlled by Dynamic Casimir Force

AbstractThe phenomenon of nonreciprocity arises from the disruption of time reversal symmetry, enabling the one‐way transfer of signals through specific channels. In the framework of cavity optomechanics, this symmetry breaking is attributed to a nonuniform radiation pressure force resulting from the interaction between light and matter. This study investigates a hybrid cavity optomechanical system (COMS) comprising two optical modes, directly coupled to each other via photon hopping interaction and indirectly via a common mechanical excitation in the form of a movable mirror, and an additional parallel metallic plate that induces a dynamical Casimir force (DCF) interaction between the plates. The two optical cavities are driven by two strong laser fields, accompanied by two weak probe classical fields from each port. The primary focus lies in exploring the nonreciprocal behavior of the light field across ports one and two, strongly manipulated by the DCF. The DCF plays a pivotal role in providing extra degrees of flexibility and manipulation in controlling the nonreciprocal signal transmission by modifying the resonance conditions of the fields within the hybrid COMS and is responsible for the amplification and swapping of information between the two ports.

Distant bipartite entanglement generation in a hybrid opto-magnomechanical system

In this work, we present a hybrid cavity opto-magnomechanical system to generate distant bipartite entanglement between different quantum carriers. Accordingly, the system consists of two cavity photons, a phonon of yttrium iron garnet (YIG), a magnon, and a phonon of membrane. Specifically, the two cavities are coupled through an optical fiber, and one of the optical cavities consists of a membrane coupled with the cavity photon through radiation pressure force. While the other cavity contains a YIG, the magnon mode connects to the cavity photon via magnetic dipole interaction and, simultaneously, couples to the mechanical resonator of the YIG through magnetostrictive interaction. We show that entanglement generation can be realized under indirectly coupled bipartitions for parameters and detunings within appropriate regimes. Furthermore, for various bipartitions, we also obtain appropriate cavity and magnon detuning values for a considerable remote entanglement. Moreover, the generation of distant bipartite entanglements and entanglement transfer between subsystems is predominantly influenced by the coupling strength. Remarkably, the distant bipartite entanglement is strongly contrary to the environmental temperature. Thus, optimizing the system’s parameters allows for the maximum possible entanglement between various quantum carriers. We believe our results could provide more stable bipartite entanglements and serve as a potential quantum interface to realize particularly long-range entanglement transfers.

Measuring the Virial Factor in SDSS DR7 Active Galactic Nuclei with Redshifted Hβ and Hα Broad Emission Lines

Under the hypothesis of gravitational redshift induced by the central supermassive black hole and based on line widths and shifts of redward-shifted Hβ and Hα broad emission lines for more than 8000 Sloan Digital Sky Survey DR7 active galactic nuclei (AGNs), we measure the virial factor in determining supermassive black hole masses. The virial factor had been believed to be independent of accretion radiation pressure on gas clouds in broad-line regions (BLRs) and only dependent on the inclination effects of BLRs. The virial factor measured spans a very large range. For the vast majority of AGNs (>96%) in our samples, the virial factor is larger than the f = 1 usually used in the literature. The f-correction makes the percent of high-accreting AGNs decrease by about 100 times. There are positive correlations of f with the dimensionless accretion rate and Eddington ratio. The redward shifts of Hβ and Hα are mainly of gravitational origin, confirmed by a negative correlation between the redward shift and the dimensionless radius of the BLR. Our results show that radiation pressure force is a significant contributor to the measured virial factor, containing the inclination effects of the BLR. The usually used values of f should be corrected for high-accreting AGNs, especially high-redshift quasars. The f-correction increases their masses by 1–2 orders of magnitude, which will make it more challenging to explain the formation and growth of supermassive black holes at high redshifts.

Quantifying Solar Radiation Pressure Effects on Dust at Small Heliocentric Distances

The dynamics of dust grains has traditionally been modeled under the assumption that the ratio of the opposing solar radiation pressure and gravitational forces is fixed for an individual, unchanging grain. However, at small heliocentric distances, this assumption is inaccurate, as the variation in radiation pressure force with heliocentric distance does not follow an inverse square law there, as the Sun cannot be approximated as a point source of light. To correct for this, we have calculated the required correction to assumed radiation pressure force values, taking into account the decrease in both the visible solar area and in the radial solar radiation force components. We present here an empirical fit to this correction, for heliocentric distances 0.028–1.00 au. This correction may be used to more accurately simulate dust motion near the Sun.

Enhanced transfer performance of sun-facing diffractive sails in solar polar imager missions

A diffractive sail represents an advancement in solar sailing technology, capable of generating tangential radiation pressure force when oriented towards the sun. This unique property allows for varied radiation pressure distributions, making it a potential candidate for complex space missions. This paper delves into the transfer performance of the sun-facing diffractive solar sail in a solar polar imager mission.We establish both the radiation pressure force model and the time-optimal control problem specific to the sun-facing diffractive solar sail in interplanetary transfers. Applying an indirect method and a combined approach of parameter optimization with the direct method, we explore how different diffractive angles and acceleration capacities affect transfer times. This research offers insights to the design and fabrication of thin novel optical metamaterial films that efficiently diffract light at appropriate angles for potential solar sails in the solar polar imager mission. Compared with reflective sails, the diffractive sail demonstrates remarkable transfer efficiency and simplicity in attitude control, making it a more suitable choice in the solar polar imager mission.

New Horizons Venetia Burney Student Dust Counter Observes Higher than Expected Fluxes Approaching 60 au

The NASA New Horizons Venetia Burney Student Dust Counter (SDC) measures dust particle impacts along the spacecraft’s flight path for grains with mass ≥10−12 g, mapping out their spatial density distribution. We present the latest SDC dust density, size distribution, and flux measurements through 55 au and compare them to numerical model predictions. Kuiper Belt objects (KBOs) are thought to be the dominant source of interplanetary dust particles in the outer solar system due to both collisions between KBOs and their continual bombardment by interstellar dust particles. Continued measurements through 55 au show higher than model-predicted dust fluxes as New Horizons approaches the putative outer edge of the Kuiper Belt (KB). We discuss potential explanations for the growing deviation: radiation pressure stretches the dust distribution to further heliocentric distances than its parent body distribution; icy dust grains undergo photosputtering that rapidly increases their response to radiation pressure forces and pushes them further away from the Sun; and the distribution of KBOs may extend much further than existing observations suggest. Ongoing SDC measurements at even larger heliocentric distances will continue to constrain the contributions of dust production in the KB. Continued SDC measurements remain crucial for understanding the Kuiper Belt and the interpretation of dust disks around other stars.

Dynamics and control of sun-facing diffractive solar sails in displaced orbit for asteroid deflection

A gravity tractor spacecraft propelled by a diffractive sail tracking a displaced orbit offers a potential option for deflecting near-Earth asteroids. This study delves into the preliminary dynamics, evaluates the deflection capabilities, and investigates the stability and control of the diffractive sail on the displaced orbit near the asteroid. Unlike reflective sails, diffractive solar sails generate tangential radiation pressure force, offering multiple advantages. These include the elimination of tilt attitude requirements, no offset angle restrictions from the target asteroid's flight direction, and superior deflection performance with an equivalent area-to-mass ratio when the diffraction angle surpasses 50deg. To maintain position, a controllable diffractive sail model using spatial light modulators, coupled with a feedback control law, is proposed. This control design stabilizes the periodic displaced orbit without necessitating tilt attitude adjustments towards the sun, as validated by our numerical simulations.

On the likely magnesium–iron silicate dusty tails of catastrophically evaporating rocky planets

ABSTRACT Catastrophically evaporating rocky planets provide a unique opportunity to study the composition of small planets. The surface composition of these planets can be constrained via modelling their comet-like tails of dust. In this work, we present a new self-consistent model of the dusty tails: we physically model the trajectory of the dust grains after they have left the gaseous outflow, including an on-the-fly calculation of the dust cloud’s optical depth. We model two catastrophically evaporating planets: KIC 1255 b and K2-22 b. For both planets, we find the dust is likely composed of magnesium–iron silicates (olivine and pyroxene), consistent with an Earth-like composition. We constrain the initial dust grain sizes to be ∼ 1.25–1.75 μm and the average (dusty) planetary mass-loss rate to be ∼ 3$\, M_{\oplus } \mathrm{Gyr^{-1}}$. Our model shows that the origin of the leading tail of dust of K2-22 b is likely a combination of the geometry of the outflow and a low radiation pressure force to stellar gravitational force ratio. We find the optical depth of the dust cloud to be a factor of a few in the vicinity of the planet. Our composition constraint supports the recently suggested idea that the dusty outflows of these planets go through a greenhouse effect–nuclear winter cycle, which gives origin to the observed transit depth time variability. Magnesium–iron silicates have the necessary visible-to-infrared opacity ratio to give origin to this cycle in the high mass-loss state.

High forward thrust metasurface beam-riding sail.

The radiation pressure force and torque on a one-dimensional bi-grating composed of a Si-SiO2 high contrast binary metagrating is analyzed for the purpose of stable beam riding whereupon a high power laser having an expanding Gaussian irradiance distribution propels the grating in outer space, free from gravitational forces. The binary metagrating structure has been simultaneously optimized to afford high forward thrust, and corrective restoring forces and torques in the event of small linear and angular disturbances. We demonstrate that stability may be enhanced at the expense of forward thrust. The validity of our metamaterial findings is reinforced owing to good agreements between finite-difference time-domain and finite element numerical methods. To reduce mass and enhance forward acceleration this laser-driven sail was designed to be free of a stabilizing boom.

Bi-circular model with test particle variable mass

This paper presents the effects of the perturbations on the motion of the test particle variable mass in the bi-circular Sun perturbed oblate Earth-Moon system where primary is taken as oblate Earth, secondary is taken as Moon and the third body is assumed as Sun. These three bodies are moving in the same plane around barycenter. The fourth and smallest body (test particle is assumed to be having variable mass with time) is moving in the space under the perturbations such as gravitational forces of the primaries, the solar radiation pressure, the coriolis and centrifugal forces. Then we determine the equations of motion, the locations of critical points, their stability and periodic orbits.

Breakthrough Sun Diving: The Rectilinear Option

A near-term possibility for utilization of Breakthrough Initiatives Project Starshot technology is application of the sun diving maneuver as a replacement for laser acceleration of highly miniaturized photon sails to interstellar velocities. This possibility was discussed during the June 2022 Breakthrough Discuss meeting in Santa Cruz California. Here, we consider application of statite-type photon sail probes to achieve rectilinear trajectories to explore outer solar system and near-interstellar destinations. Statite-Type solar photon sails are sufficiently thin and reflective that solar radiation pressure force on the sail exactly balances the solar gravitational force. In such a force-free environment, the spacecraft exits the solar system at its pre-sail-deployment solar-orbital velocity. Here we consider departures from a circular 1 AU solar orbit, the perihelion of a 0.7-1 AU elliptical solar orbit and the perihelion of a 0.3-1 AU solar orbit. Possible outer-solar system destinations of possible interest to Breakthrough Initiatives extraterrestrial-life/artifact -search researchers include Europa, Titan, Enceladus, Methone, and Arrokoth. More distant possible objectives are ‘Oumuamua and the Sun’s inner gravitational focus. To achieve a rectilinear trajectory, the sail must be oriented normal to the Sun and spacecraft areal mass thickness is 1.46 × 10-3 kg/m2. Current sail technology is reviewed to determine whether it can achieve the required areal mass thickness.

Acceleration of Ions by the Force of Radiation Pressure during the Interaction of an Extremely Intense Pulse of Circularly Polarized Laser Radiation with a Solid Target

Acceleration of Ions by the Force of Radiation Pressure during the Interaction of an Extremely Intense Pulse of Circularly Polarized Laser Radiation with a Solid Target