The coupling of compressional and transverse hydromagnetic waves is studied in the cold and inhomogeneous outer magnetosphere. A general computer program has been developed for a dipole model. This model allows a realistic spatial variation of Alfven speed and includes dipole geometric effects. The propagation and the structure of each mode are analyzed on a two‐dimensional map of a meridian plane. The properties of coupling are also investigated through time histories and wave frequency spectra. The highly spatially structured form of transverse and compressional waves is shown on the meridian plane. The theory of global compressional mode damping is compared with the numerical results. We have found a set of global modes whose spatial structure is complicated due to the inhomogeneity of the dipole geometry. These global modes are strongly coupled to field line resonances when the global mode frequency is harmonically matched to the toroidal resonant frequency. The coupling of the two modes results in relatively large‐amplitude oscillations along the resonant field lines.

Our findings provide support for the reliability and validity of the Korean JSPE-S and indicate that it can serve as a useful instrument for assessing empathy among Korean medical students.

The radial mode structure of Pi2 pulsations in the inner magnetosphere (L < 7) and its relation to the plasmapause are studied using data acquired by the Combined Release and Radiation Effects Satellite (CRRES) between August 1990 and September 1991. Low‐latitude Pi2 pulsations detected on the ground at Kakioka (L = 1.25) are used as the reference signal to determine the relative amplitude and phase of the electric field oscillations detected at CRRES. The plasmapause is identified using electron density inferred from the plasma wave spectra observed on CRRES. Pi2 events at CRRES are defined to be 10‐min intervals of high coherence between oscillations in the Kakioka horizontal northward magnetic field (H) and CRRES dusk‐to‐dawn electric field (Eφ) components within the Pi2 band (6–25 mHz). The Eφ component represents the poloidal oscillation of the geomagnetic field lines for satellite local times near midnight. Fifty‐five high‐coherence Eφ‐H Pi2 events occurred when both CRRES and Kakioka were within 3 hours of magnetic midnight. For these events CRRES was on L shells ranging from 2 to 6.5 and was either in the plasmasphere or in the close vicinity of the plasmapause, providing evidence for the plasmaspheric origin of low‐latitude Pi2 pulsations. The amplitude of Eφ varied significantly but there is an indication of a maximum near L = 4. The phase of Eφ (relative to Kakioka H) remained near −90° at all distances. These properties are consistent with the radial structure of the fundamental cavity mode oscillations confined in the plasmasphere. For some events observed at L > 3.5 it was also possible to determine the amplitude and phase of the compressional component Bz at CRRES. In contrast to Eφ, the phase of Bz (relative to H) was clustered both at ∼180° and ∼0 for events occurring near the plasmapause. This observation still is consistent with the cavity mode according to a numerical simulation using a dipole magnetic field and a realistic plasmapause plasma density structure, which indicates that the node of Bz is located near the plasmapause. Depending on the satellite position relative to the node, the phase can be either –180° or 0. A negative correlation is found between the Pi2 frequency and the distance of the plasmapause, which is additional support for the cavity mode origin of low‐latitude Pi2 pulsations.

Genomic RNA from the human prototype strain H of the hepatitis C virus (HCV-H) has been molecularly cloned and sequenced. The HCV-H sequence reported consists of 9416 nucleotides including the 5' and 3' untranslated regions. HCV-H shows 96% amino acid identity with the American isolate HCV-1 but only 84.9% with the Japanese isolates HCV-J and HCV-BK. In addition to the hypervariable region (region V) previously identified in the putative E2 domain, three other variable domains were identified: region V1 (putative El), region V2 (putative E2), and region V3 (putative NS5). These regions appear rather conserved (86-100%) among the American isolates (HCV-1 and HC-J1) or among various Japanese isolates (HCV-J, HCV-BK, HCV-JH, and HC-J4) but show striking heterogeneity when the two subgroups are compared (42-87.5% amino acid difference). A structural similarity between the 5'-terminal hairpin structure of HCV and of poliovirus was observed. This study further suggests the existence of at least two genomic subtypes of HCV and confirms a distant relationship between HCV and pestiviruses.

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The propagation of MHD waves depends on a local Alfven speed and ambient geometry. The dynamical properties of MHD waves in the plasmasphere and magnetosphere are investigated by assuming a realistic Alfven speed profile in a dipole field. The WKB approximation is used to determine the cutoff boundaries and estimate the wave dispersion over a whole meridional plane. It is found that most wave energy may be transmitted effectively into the inner magnetosphere near the equatorial region, since the reflection of incoming waves at the plasmapause becomes weakest at the equator. It is also examined how the transmission from the outer magnetosphere to the inner magnetosphere depends on wave frequencies and azimuthal wavenumbers. The cutoff boundaries of wave propagation are quantitatively determined for each mode and wavenumber, which show various structures on the meridian. The results suggest that the propagation region may consist of two separable domains of the inner and outer magnetosphere for a relatively low‐frequency wave. The inner region of propagation appears to be a distorted torus around the dipole axis. Such spatial separation of the two regions becomes weak and gradually interconnected for the waves with a relatively small azimuthal wavenumber or high frequency. The wave spectra and energy distribution are also investigated for different azimuthal wavenumbers. The numerical results show that the cavity modes may exist in the plasmasphere even at the absence of the outer magnetospheric boundary, which is found to be strongly associated with the characteristics of wave parameters. In particular, it is suggested that the plasmaspheric cavity modes, in the nightside region, may play a crucial role in producing Pi 2 pulsations. In addition, theories of waveguide and cavity modes based on the dipole model are discussed in detail.

Magnetohydrodynamic (MHD) oscillatory processes in different plasma systems, such as the corona of the Sun and the Earth's magnetosphere show interesting similarities and differences, which so far received little attention and remain underexploited. The successful commissioning within the past ten years of SDO, Hinode, STEREO and THEMIS spacecraft, in combination with matured analysis of data from earlier spacecraft (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) makes it very timely to survey the breadth of observations giving evidence for MHD oscillatory processes in solar and space plasmas, and state-of-the-art theoretical modelling. The paper reviews several important topics, such as Alfvénic resonances and mode conversion; MHD waveguides, such as the magnetotail, coronal loops, coronal streamers; mechanisms for periodicities produced in energy releases during substorms and solar flares, possibility of Alfvénic resonators along open field lines; possible drivers of MHD waves; diagnostics of plasmas with MHD waves; interaction of MHD waves with partly-ionised boundaries (ionosphere and chromosphere). The review is mainly oriented to specialists in magnetospheric physics and solar physics, but not familiar with specifics of the adjacent research fields.

Abstract.ULF pulsations have been numerically studied in a new threedimensional dipole model, which allows a realistic Alfven speed profile for the plasmasphere and outer magnetosphere in the tailward region. This model includes more realistic boundary conditions at the outer boundary, allowing for partial reflection at the magnetopause and escape of wave energy down the tail. We investigate how Pi2 modes develop in time when an impulse associated with the substorm onset is assumed. It is shown that discrete compressional modes, which are initially excited by the plasmasphere, persistently arise in the nightside region. Our numerical results suggest that Pi2 pulsations are strongly associated with these virtual resonances in the plasmasphere. Wave spectra are examined both at the equator and the ionosphere. We discuss and compare them with current theoretical and observational characteristics.