隨著PSP的近日探測任務和太陽軌道器 (SolO) 計畫在未來逐年增高傾角的高傾角軌道持續進行探測，我們認為現在正是對近日區域的奈米塵埃電動力學進行更深入的研究的時機，以便更詳細的分析由PSP和SolO所提供的三維觀測數據。因此我們在此提出了一項關於源自太陽附近的帶電奈米塵埃行為的全面研究，此研究以三維MHD太陽風模型為基礎，並考慮了勞倫茲力以及太陽輻射壓力對塵埃粒子的加速。我們將討論在太陽周期的不同階段，不同尺寸的微小塵埃粒子普遍的三維空間分布及其動力學行為。 ;For decades, information on the near-solar dust cloud has been acquired through not only remote-sensing observations but also the detections of high-speed nanodust impacts by spacecraft, such as Ulysses, Wind, SOHO, and more recently, the Parker Solar Probe (PSP). These nanodust impact measurements are generally believed to result from the so-called hyperbolic beta-meteoroids, which break apart from larger bodies through collision or sublimation in the near-sun region. These tiny particles can be propelled radially forward by solar radiation pressure. Moreover, when fragmented small enough, they can also be accelerated by electromagnetic forces. Note that while the brightness distribution of the near-solar dust cloud in terms of F-corona has an outer limit on its latitudinal extension to no more than 40°, the Ulysses spacecraft detected β-meteoroid impacts during its polar passage(s). Several studies suggested that the electromagnetic force in the heliosphere is the leading cause of these high heliolatitude β-meteoroids.
In other words, the electrodynamics of nanodust is essential to shape the three-dimensional (3D) trajectories of the nanodust ejected from the near solar dust cloud. With the planned near-sun approach of PSP and the high inclination orbits of the Solar Orbiter (SolO), we believe it is timely to conduct more in-depth studies of the nanodust electrodynamics in the near-sun region in preparation for more detailed analyses of the Parker Solar Probe and Solar Orbiter observations in 3D. Here we present a comprehensive study of the charged nanodust behavior originating from the vicinity of the Sun, based on a 3D MHD solar-wind model by taking into account Lorentz force and solar radiation pressure acceleration. General results on the 3D spatial distributions and dynamical behaviors of tiny grains of different sizes at different phases of the solar cycle will be discussed.
