Observations of solar flare gamma-rays and protons

Solar flare gamma-rays (4 to 7 MeV) and protons (8 to 500 MeV) were simultaneously observed from six flares on 1 Apr., 4 Apr., 27, Apr. 13, May 1981, 1 Feb. and 6 June 1982 by the Hinotori and GMS satellites. The relationship between 4 to 7 MeV gamma-ray fluences and peak 16 to 34 MeV proton fluxes for these flares are analyzed. It does not reveal an apparent correlation between these two parameters. The present result implies that the protons producing gamma-rays and the protons observed near the Earth do not always belong to the same population

Extreme midlatitude cyclones and their implications for precipitation and wind speed extremes in simulations of the Maunder Minimum versus present day conditions

Extreme midlatitude cyclone characteristics, precipitation, wind speed events, their inter-relationships, and the connection to large-scale atmospheric patterns are investigated in simulations of a prolonged cold period, known as the Maunder Minimum from 1640 to 1715 and compared with today. An ensemble of six simulations for the Maunder Minimum as well as a control simulation for perpetual 1990 conditions are carried out with a coupled atmosphere-ocean general circulation model, i.e., the Climate Community System Model (CCSM). The comparison of the simulations shows that in a climate state colder than today the occurrence of cyclones, the extreme events of precipitation and wind speed shift southward in all seasons in the North Atlantic and the North Pacific. The extremes of cyclone intensity increases significantly in winter in almost all regions, which is related to a stronger meridional temperature gradient and an increase in lower tropospheric baroclinicity. Extremes of cyclone intensity in subregions of the North Atlantic are related to extremes in precipitation and in wind speed during winter. Moreover, extremes of cyclone intensity are also connected to distinct large-scale atmospheric patterns for the different subregions, but these relationships vanish during summer. Analyzing the mean 1,000hPa geopotential height change of the Maunder Minimum simulations compared with the control simulation, we find a similar pattern as the correlation pattern with the cyclone intensity index of the southern Europe cyclones. This illustrates that changes in the atmospheric high-frequency, i.e., the simulated southward shift of cyclones in the North Atlantic and the related increase of extreme precipitation and wind speed in particular in the Mediterranean in winter, are associated with large-scale atmospheric circulation change

Rising global economic power by China to challenge new global order

This paper’s arguments guide Chinese political economy. This analytical idea is based on Rodrik’s political-economy trilemma: global economic integration, democracy, and national sovereignty. Chinese policymakers face a trade-off among three policy goals: (hyper-) globalization, democracy, and national sovereignty. China’s President Xi and the Chinese Communist Party (CCP) have chosen global economic integration and national sovereignty (fewer human rights). To reflect the analytical idea, which can measure the length of a vector, is a mathematics methodology. As a result, Chinese political events such as the Great Proletarian Cultural Revolution in 1966, the death of Mao Zedong in 1976, and the choice of Chinese President Xi Jinping as General Secretary of the Communist Party in 2012 had an impact on reshaping when the length of vector (the sphere’s radius of 2) was more than 2. The future direction of China will lead to a “Golden Straitjacket.” The “Golden Straitjacket.” makes a country push forward trade liberalization and national sovereignty — i.e., democracy is constrained. Chinese policy has changed to stronger centralization of political power and decision-making for President Xi and the CCP. Also, China expands a global economic integration and national sovereignty. However, China needs to contribute to globalization without causing more conflicts to Western countries. In other words, China should be loath to relinquish the individual and national benefits of integrated international economies. “Fast and furious” is the first step of globalization for a peaceful world

Shadow Exchange Rates – Changing the Winds with Headwinds and Tailwinds

This paper summarizes the arguments and counterarguments within the academic discussion on the issue of double exchange rates – official exchange rates and unofficial exchange rates – produced by the cryptocurrency bitcoin (BTC). The policy conclusion of this research is that cryptocurrency exchange rates ought to be monitored by authorized organizations because of unsustainable price volatility. The relevance of the decision of this scientific problem is that some unofficial exchange rates are likely to have higher volatility caused by BTC’s bubble and burst than by the official exchange rate

Looking a Gift Horse in the Mouth: A Reassessment of the Impact of the Hershey Trust

This paper summarizes arguments and counterarguments driving academic discussion about the Milton Hershey School (MHS) and the Hershey Company’s control mechanism, enacted by the Hershey Trust (HT). It then studies the Hershey Trust’s governance with respect to ethics, budget sources, and management, focusing on how the Hershey Company exercises corporate control over MHS. My main tool of analysis is an event study, which estimates a particularly abnormal response of the Hershey Company’s stock price to potentially disruptive developments. Empirical results indicate that the Hershey Company has not been greatly influenced by the Hershey Trust. Abnormal return of the Hershey Company’s stock price is skewed, and it has an asymmetric probability distribution after June 2016. However, the Hershey Trust continues to indirectly manage and control the Hershey Company. The Hershey Trust, accordingly, is a de facto ‘industrial foundation’. Thus, charitable trustees of the Hershey Trust affect the Hershey Company’s stock price and management. The HT and the MHS had mistaken a governance because the diversification lies with beneficiations of the trust per se, not shareholders of the Hershey Company. The HT and MHS should end their puppet dominance of the Hershey Company because the HT’s and MHS’s future 501(c)(3) status will be jeopardized. Overall, this paper presents analysis and empirical results, aimed at building a more charitable organization. The audience for this paper includes policymakers, regulators, and academics

Low-energy properties of two-dimensional quantum triangular antiferromagnets: Non-perturbative renormalization group approach

We explore low temperature properties of quantum triangular Heisenberg antiferromagnets in two dimension in the vicinity of the quantum phase transition at zero temperature. Using the effective field theory described by the $SO(3)\times SO(2)/SO(2)$ matrix Ginzburg-Landau-Wilson model and the non-perturbative renormalization group method, we clarify how quantum and thermal fluctuations affect long-wavelength behaviors in the parameter region where the systems exhibit a fluctuation-driven first order transition to a long-range ordered state. We show that at finite temperatures the crossover from a quantum $\phi^6$ theory to a renormalized two-dimensional classical nonlinear sigma model region appears, and in this crossover region, massless fluctuation modes with linear dispersion a la spin waves govern low-energy physics. Our results are in good agreement with the recent experimental observations for the two-dimensional triangular Heisenberg spin system, NiGa$_2$S$_4$.Comment: 14 pages,7 figures, version accepted for publication in Physical Review

Spin current and magneto-electric effect in non-collinear magnets

A new microscopic mechanism of the magneto-electric (ME) effect based on the spin supercurrent is theoretically presented for non-collinear magnets. The close analogy between the superconductors (charge current) and magnets (spin current) is drawn to derive the distribution of the spin supercurrent and the resultant electric polarization. Application to the spiral spin structure is discussed.Comment: 5 pages, 2 figure

Radio Spectral Evolution of an X-ray Poor Impulsive Solar Flare: Implications for Plasma Heating and Electron Acceleration

We present radio and X-ray observations of an impulsive solar flare that was moderately intense in microwaves, yet showed very meager EUV and X-ray emission. The flare occurred on 2001 Oct 24 and was well-observed at radio wavelengths by the Nobeyama Radioheliograph (NoRH), the Nobeyama Radio Polarimeters (NoRP), and by the Owens Valley Solar Array (OVSA). It was also observed in EUV and X-ray wavelength bands by the TRACE, GOES, and Yohkoh satellites. We find that the impulsive onset of the radio emission is progressively delayed with increasing frequency relative to the onset of hard X-ray emission. In contrast, the time of flux density maximum is progressively delayed with decreasing frequency. The decay phase is independent of radio frequency. The simple source morphology and the excellent spectral coverage at radio wavelengths allowed us to employ a nonlinear chi-squared minimization scheme to fit the time series of radio spectra to a source model that accounts for the observed radio emission in terms of gyrosynchrotron radiation from MeV-energy electrons in a relatively dense thermal plasma. We discuss plasma heating and electron acceleration in view of the parametric trends implied by the model fitting. We suggest that stochastic acceleration likely plays a role in accelerating the radio-emitting electrons.Comment: 22 pages, 10 figure

Gamma-Ray Spectra & Variability of the Crab Nebula Emission Observed by BATSE

We report ~ 600 days of BATSE earth-occultation observations of the total gamma-ray (30 keV to 1.7 MeV) emission from the Crab nebula, between 1991 May 24 (TJD 8400) and 1994 October 2 (TJD 9627). Lightcurves from 35-100, 100-200, 200-300, 300-400, 400-700, and 700-1000 keV, show that positive fluxes were detected by BATSE in each of these six energy bands at significances of approximately 31, 20, 9.2, 4.5, 2.6, and 1.3 sigma respectively per day. We also observed significant flux and spectral variations in the 35-300 keV energy region, with time scales of days to weeks. The spectra below 300 keV, averaged over typical CGRO viewing periods of 6-13 days, can be well described by a broken power law with average indices of ~ 2.1 and ~ 2.4 varying around a spectral break at ~ 100 keV. Above 300 keV, the long-term averaged spectra, averaged over three 400 d periods (TJD 8400-8800, 8800-9200, and 9200-9628, respectively) are well represented by the same power law with index of ~ 2.34 up to ~ 670 keV, plus a hard spectral component extending from ~ 670 keV to ~ 1.7 MeV, with a spectral index of ~ 1.75. The latter component could be related to a complex structure observed by COMPTEL in the 0.7-3 MeV range. Above 3 MeV, the extrapolation of the power-law continuum determined by the low-energy BATSE spectrum is consistent with fluxes measured by COMPTEL in the 3-25 MeV range, and by EGRET from 30-50 MeV. We interpret these results as synchrotron emission produced by the interaction of particles ejected from the pulsar with the field in different dynamical regions of the nebula system, as observed recently by HST, XMM-Newton, and Chandra.Comment: To be published in the November 20, 2003, Vol 598 issue of the Astrophysical Journa