Tuning of relative spatial distributions of a two-component ion system to improve sympathetic cooling efficiency

Herein, a fine-tuning method is proposed for the spatial distributions of a mixed three-dimensional (3D) ion system in dual radio frequency (RF) linear Paul traps to achieve efficient sympathetic cooling. The dual RF field matching, efficient capture method and transient process of the intrinsic micromotion of the mixed ion system are analyzed quantitatively by numerical simulations. The 3D correlation coupling characteristics between intrinsic micromotion and secular motion of ion system are obtained. It is found that reasonable low-frequency trapping potential can produce ultra-low-frequency pulling effect on ions with low mass-to-charge ratio (M/Q), which is beneficial to the dynamic coupling between ions with large M/Q differences. The effects of equivalent stiffness coefficients [Formula: see text] on the relative spatial configuration and dynamic coupling process of mixed 3D ion crystals with large M/Q differences are discussed. By tuning [Formula: see text], radial distributions of laser-cooled ions (LCIs) and sympathetically cooled ions (SCIs) that do not conform to the rules based on M/Q are realized. The optimum sympathetic-cooling efficiency occurs, where [Formula: see text] is approximately equivalent to [Formula: see text]. These results are applicable to studies such as cold ion clocks, quantum logic manipulation, antimatter synthesis, regulation of cold chemical reaction, and precise spectral measurements based on sympathetic cooling.

Steady-state rotational motion of the Photon M-2 satellite

At the end of the flight, the attitude motion of the Photon M-2 satellite (it was in orbit 2005.05.31-2005.06.16) can be described by a generalized conservative system of differential equations. The secular change in the own kinetic moment of this satellite is described by the so-called evolutionary equations of Beletsky, which also form a generalized conservative system. The preprint examines the relationship between these systems. The satellite motion equations are reduced to equations of the 4th order describing the motion of the satellite axis of symmetry. Beletsky's equations are of the second order and describe the secular motion of the ort of the satellite's own kinetic moment. The solutions of these systems of equations corresponding to the real movements of the satellite are, respectively, conditionally periodic and periodic. The solutions of the 4th-order system are dominated by two frequencies – high and low ones. The spectral analysis showed that the low frequency coincides with the frequency of solutions of Beletsky’s equations. And the solutions of these equations coincide with the low-frequency component in the solution of the 4th-order system with respect to the variables that determine the direction of the axis of symmetry of the satellite.

GPS-DERIVED SECULAR VELOCITY FIELD AROUND SANGIHE ISLAND AND ITS IMPLICATION TO THE MOLUCCA SEA SEISMICITY

<p><em>Sangihe-Moluccas region is the most active seismicity in Indonesia. Between 2015 to 2018 there is four M6 class earthquake occurred close to the Sangihe-Moluccas region. These seismic active regions representing active deformation which is recorded on installed GPS for both campaign and continuous station. However, the origin of those frequent earthquakes has not been well understood especially related to GPS-derived secular motion. Therefore, we intend to estimate the secular motion inside and around Sangihe island. On the other hand, we also evaluate the effect of seismicity on GPS sites. Since our GPS data were conducted on yearly basis, we used an empirical global model of surface displacement due to coseismic activity. We calculate the offset that may be contained in the GPS site during its period</em><em>. </em><em>We remove the offset and estimate again the secular motion using linear least square. Hence, in comparison with the secular motion without considering the seismicity, we observe small change but systematically shifting the motion. We concluded the seismicity in the Molucca sea from 2015 to 2018 systematically change the secular motion around Sangihe Island at the sub-mm level. Finally, we obtained the secular motion toward each other between the east and west side within 1 to 5.5 cm/year displacement. </em></p>

Coseismic Displacement Accumulation Between 1996 and 2019 Using A Global Empirical Law on Indonesia Continuously Operating Reference Station (InaCORS)

Indonesia archipelago is one of the most populated country with active and complex tectonic zone in the world. Plate boundaries were assembled by four major plate which made the region not only vulnerable to earth-hazard but also prone to semi-dynamic reference frame. However, influence of transient deformation such as coseismic displacement due to large amount of small to intermediate earthquakes (< Mw 6) on the geodetic networks is remain poorly understood. Geospatial Information Agency occupied permanent and continuous GPS networks since 1996 but rapidly increase in 2010. Based on simulated empirical law of coseismic crustal deformation, we estimate the cumulative displacement due to coseismic step on Indonesia Continuous Operating Reference Stations (InaCORS). We utilize the position of the observation network and earthquake hypocentral with estimated moment magnitude. Our result suggesting small to intermediate earthquakes are indispensable for estimating secular motion and potentially contribute the cumulative offset associated with the transient postseismic deformation.

Geodetic vertical velocities affected by recent rapid changes in polar motion

Secular motion of Earth's rotation pole results in large-scale secular deformation of Earth. Here, we investigate the magnitude of the deformation that has resulted from the rapid motion of the rotation pole to the east since ∼2005. We show that geodetic (GNSS, DORIS, VLBI and SLR) estimates of vertical velocity since ∼2005 have been biased by up to ±0.38 mm yr–1 relative to the longer-term deformation pattern. The largest signals occur within regions that include the U.S. Pacific Coast, Europe and South Pacific islands where geodetic measurements provide essential measurements of tide-gauge vertical movement and important constraints on models of glacial isostatic adjustment. Consequently, geodetic vertical velocities based on recent data should not be interpreted as being identical to centennial or longer term vertical land movement. Since 2010 the effect is further amplified by the overprediction of the IERS polar motion model relative to the ongoing secular change in pole position—during this time geodetic vertical velocities based on the IERS pole tide model are not just biased relative to the long-term rates but also from actual post-2010 Earth deformation. For geophysical or reference frame studies seeking geodetic vertical velocities that are representative of decadal timescales, where interannual variation is considered noise, the correction for this non-linear effect is straightforward, requiring an elastic computation using a reference rate of polar motion that is linear over the timescales of interest.