Inversion Phenomena of the Anisotropies of the Hamiltonian and the Wave-Function in the Distorted Diamond Type Spin Chain

We investigate the ground-sate phase diagram of the XXZ version of the S=1/2 distorted diamond chain by use of the degenerate perturbation theory near the truncation point. In case of the XY-like interaction anisotropy, the phase diagram consists of the Neel phase and the spin-fluid phase. For the Ising-like interaction anisotropy case, it consists of three phases: the ferrimagnetic phase, the Neel phase and the spin-fluid phase. The magnetization in the ferrimagnetic phase is 1/3 of the saturation magnetization. The remarkable nature of the phase diagram is the existence of the Neel phase, although the interaction anisotropy is XY-like. And also, the spin-fluid phase appears in spite of the Ising-like interaction anisotropy. We call these regions "inversion regions".Comment: 7 pages, 4 figure

Extreme magnetic field variations during the October 2003 superstorm

From October to November, 2003 the sun became very active. The plural numbers of active region appeared on the solar surface. The most prominent one was the number 486, which yielded extremely large flares X17/4B at 0951UT on October 28, and X10/2B at 2037UT on October 29. These big flares hurled massive coronal mass ejections (CMEs) toward the earth. In this paper the solar-terrestrial relationship during the October super magnetic storms is discussed. Two fast moving clouds of gas from the sun swept the earth and sparked extreme geomagnetic storms producing the big ground magnetic field depressions of approximately - 350nT and - 400nT of Dst. Several interesting magnetic field variations observed in interplanetary space and their relationships to the ground magnetic field variations are discussed. Topics are as follows: 1) magnetic field polarity changes of the north-south component Bz of interplanetary magnetic field conveyed with the interplanetary coronal mass ejections (ICMEs) and their response to the magnetic field variations on the ground, 2) large amplitude tail flapping motions observed in the distant tail at about - 160Re, 3) large amplitude Pc 5 oscillations globally observed on the ground during the recovery phase of the super magnetic storm, and 4) large amplitude Pc 3 ULF waves observed in space from upstream through the magnetosheath to the dusk-side outer magnetosphere

Detection of the onset time of Pi 2 pulsations by using wavelet analysis

We have developed an algorithm for automatic detection of the onset of Pi 2 pulsations by using the wavelet transform. It is found that the Cauchy wavelet with proper parameters has a time resolution higher than that of the Gabor wavelet, and is suitable for detecting Pi 2 onset. It is revealed that the time of power peak of the Cauchy wavelet transform is given within one to three minutes after the onset of Pi 2. This time lag has been automatically compensated in the present algorithm, and it is shown that the onset time of almost all Pi 2 events can be determined with an accuracy of one minute

Similarity and dissimilarity of conjugate relationships of Pi magnetic pulsations observed during excellent similar auroras

Similarity and dissimilarity of conjugate relationships of Pi magnetic pulsations observed during excellent similar auroras at the conjugate stations, Tjornes in Iceland and Syowa Station in Antarctica are examined. The study revealed that characteristic Pi pulsations, Pi 2 pulsations and impulsive Pi 1 pulsations were prominently observed with a close relationship to aurora activities. During the substorm growth phase they showed a good similarity between the conjugate stations. How ever, at the onset of substorm expansion, the appearance of Pi pulsations showed prominent dissimilarity between the conjugate stations, suggesting that there might be some asymmetry of the ionosphere and magnetosphere conditions in between the northern and the southern hemispheres

Ground state of an S=1/2S=1/2 distorted diamond chain - model of Cu3Cl6(H2O)2⋅2H8C4SO2\rm Cu_3 Cl_6 (H_2 O)_2 \cdot 2H_8 C_4 SO_2

We study the ground state of the model Hamiltonian of the trimerized $S=1/2$ quantum Heisenberg chain $\rm Cu_3 Cl_6 (H_2 O)_2 \cdot 2H_8 C_4 SO_2$ in which the non-magnetic ground state is observed recently. This model consists of stacked trimers and has three kinds of coupling constants between spins; the intra-trimer coupling constant $J_1$ and the inter-trimer coupling constants $J_2$ and $J_3$. All of these constants are assumed to be antiferromagnetic. By use of the analytical method and physical considerations, we show that there are three phases on the $\tilde J_2 - \tilde J_3$ plane ($\tilde J_2 \equiv J_2/J_1$, $\tilde J_3 \equiv J_3/J_1$), the dimer phase, the spin fluid phase and the ferrimagnetic phase. The dimer phase is caused by the frustration effect. In the dimer phase, there exists the excitation gap between the two-fold degenerate ground state and the first excited state, which explains the non-magnetic ground state observed in $\rm Cu_3 Cl_6 (H_2 O)_2 \cdot 2H_8 C_4 SO_2$. We also obtain the phase diagram on the $\tilde J_2 - \tilde J_3$ plane from the numerical diagonalization data for finite systems by use of the Lanczos algorithm.Comment: LaTeX2e, 15 pages, 21 eps figures, typos corrected, slightly detailed explanation adde

Compressional Pc 4 pulsations observed at synchronous orbit

Magnetic oscillations of Pc 4 type ULF waves in the period range from 40 to 180s are examined using the ATS-6 magnetometer data during the period from June 1 to August 31,1974. During this period the satellite was located at a magnetic latitude of 10°. It is found that there are two typical types of waves; compressional (meridionally polarized) and transverse (azimuthally polarized) waves. The transverse waves occur mainly in the early morning hours, while the compressional waves occur in the afternoon hours. The compressional waves exhibit rather shorter periods (40-110s) than the periods of the transverse waves (90-180s). The calculation of eigen mode period using the recent GEOS 2 plasma density data shows that the period of compressional waves agrees well with the calculated period of the second harmonic oscillation of the magnetic field line passing through the satellite. The compressional waves occur closely associated with ring current proton flux oscillations. A bounce resonant condition between azimuthally propagating waves and ring current protons is examined. The resonant condition is satisfied when the azimuthal angular wave number is longer than ∿100. It suggests that these compressional Pc 4 waves can not be observed on the ground due to the ionospheric screening effect

Dynamic spectral study of Pc 3-5 magnetic pulsations observed in the north polar cusp region

Dynamic spectral characteristics of magnetic pulsations in the frequency range from Pc 3 to Pc 5 are examined on the basis of simultaneous observations at Cambridge Bay in the north polar cusp region and Fort Smith in the auroral zone. Both stations are located at almost the same longitude. In the dynamic spectra observed at both stations two predominant spectral bands are generally seen in the frequency ranges of Pc 3 (20-80mHz) and Pc 4/5 (3-10mHz). Although spectral peaks in the Pc 3 and Pc 4/5 bands are shown at almost the same frequencies for both stations, sharpness (Q value) of the peaks is very different between the stations. The spectral peaks at Fort Smith are much sharper than those at Cambridge Bay. These observed features are discussed in the light of propagation and resonance mechanism of Pc 3 and Pc 4/5 waves in the magnetosphere

Magnetic Pulsations in the Period Range from 40 to 170 Seconds Observed at Synchronous Orbit: Comparison of Satellite and Ground Data

Monochromatic sinusoidal oscillations in the period range from 40 to 170s were frequently observed by a synchronous satellite, ATS-6,in August of 1975. During the observation period the satellite was located at 35°east longitude and close to the geomagnetic equatorial plane. The present paper concerns with an examination on wave characteristics of these monochromatic sinusoidal oscillations and on an oscillation mechanism by analyzing numerous wave events observed by ATS-6. The results indicate that oscillations show a clear local time variation in the period, shorter in the morning and longer in the evening. With regard to an oscillation mechanism our conclusion strongly supports a hypothesis that the second harmonic resonance oscillation of standing Alfven wave is most probably an oscillation mode near the synchronous orbit at 6.6 earth radii. Another examination of the satellite and ground correlation of those waves indicates that there is a clear evidence of a rotation of the principal axis of the waves observed by the satellite and on the ground