A three-dimensional ion imaging spectrometer has been designed and calibrated by ion trajectories simulations. We present a recipe for the verification of the calibration by obtaining kinetic energy () distribution from the recorded flight times alone and consequently correlating the two spectra.

Molecules ionized by intense (10–100 TW/cm2) and ultrashort (tens of femtoseconds) laser fields undergo rotation and alignment mediated through their polarizability. The expected alignment is indeed observed in the case of O2 molecules ionized by intense laser pulses of 800 nm wavelength and 25 fs duration, as observed through velocity imaging of the fragments. Strikingly, when 35 fs pulses of 400 nm wavelength of comparable intensity are employed, an anomalous hindering of this alignment is observed. In both cases, we propose dissociation pathways for the energetic ions consistent with the recorded kinetic energy distributions. Using a semiclassical model of induced rotation of the molecular ion that involves polarizabilities of the participating excited states, both behaviors are reproduced. The model suggests that the difference in the observations can be attributed to a transient negative polarizability in an intermediate state of the proposed pathway.

With an increased focus on green transportation, hybrid energy storage systems (HESS) for Electric Vehicles (EV) are gaining importance in recent years. In this paper, we propose a control strategy for optimal distribution of power demand between battery and supercapacitor (SC) in a HESS, as well as efficient utilization of the regenerative braking power. A DC/DC boost converter based power splitting strategy has been proposed. Two control blocks are proposed for charging and discharging of energy storage, which reduces the rate of discharge current, thereby improving the health and life of the battery. Simulation results are presented for the proposed circuit and compared with the state-of-the-art topology. The results show that the proposed control strategy improves State-of-Charge (SOC) of the battery from 84% to 94.4% in comparison with only battery held systems. The depth of discharge (DOD) also improved by 10.4%, which helps to enhance the range of the HESS based EV from a single charge.

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