R. Pérez Enríquez

Excitation of plasma waves in the ionosphere caused by atmospheric acoustic waves

The transformation of atmospheric acoustic waves into plasma waves in the ionosphere is investigated. The transformation mechanism is based on plasma wave exitation by growing acoustic waves, when a frequency/wavelength matching situation is reached. The interaction of acoustic and plasma waves occurs through collisions of neutral particles with ions. For the case of ion-sound waves, oscillations on ion cyclotron frequency and Alfvén waves is considered. A peculiarity of Alfvén waves is the wide frequency band which may be stimulated through wave-wave interaction.

Collapse of nonlinear surface dust sound waves in the dusty plasma–dielectric system

The nonlinear monopulses of surface dust sound waves in the dusty plasma–dielectric system are investigated. The dusty plasma includes positive ions as the light component and negative dust as the heavy one. The set of hydrodynamic equations for dust in addition to the Poisson equation is used. The Boltzmann distribution is used for the ions. Electric and hydrodynamic boundary conditions are applied to the smooth interface. When moderate nonlinearity manifests itself near the interface, variations of dust concentration reach extremely high values, and collapse of the surface dust sound waves occurs. Estimations have demonstrated that the above-mentioned phenomena can be observed in natural dusty plasmas such as under volcano eruptions.

Interaction of linear and nonlinear ion-sound waves with inclusions of dusty plasma

Diverse phenomena exist in the ionosphere caused by the presence of dusty plasma objects. These have a bearing on problems of space communication and possibly on the Earths weather, among others. Therefore, it is very important to study them so that many questions on the subject can be answered. In this paper, the interaction of plasma waves with these objects is studied and some instrumentation to measure such interactions is proposed. In particular, the interaction of ion-sound waves (ISW) by non-soliton and soliton pulses propagating in dusty plasma is investigated. It is shown that inclusions of dusty components of the ionosphere plasma behave as resonators for non-soliton pulses, so that ISW are excited. Korteveg?de Vries (KdV) solitons practically do not resonate with the inclusions of dusty plasma. Instead, the presence of dusty plasma inclusions can lead to the presence of transverse instabilities and the eventual destruction of the KdV solitons.

The intense solar activity of March 1989 as a precursor for the occurrence of an ENSO by the end of 1989

We studied the occurrence of ENSO (El Niño-Southern Oscillation) events in relation to solar activity conditions and we found that the events are distributed in two populations, one that could be associated with low latitude coronal holes which occur along the ascending phase of the cycle and the other one which could be related to polar holes present at the end of the descending phase. As highly anomalous solar activity, in terms of flares and coronal holes, occurred in March of this year, we propose that an ENSO event is likely to occur by the end of the year.

Propagation of linear and nonlinear ion-sound monopulses in dusty plasma waveguides

The propagation of monopulse (baseband) linear and nonlinear ion-sound waves in dusty plasma waveguides is investigated. These waveguides are formed by prolonged inclusions of dusty plasma within the electron-ion one. The planar and cylindrical geometries are studied numerically. It has been demonstrated that nonlinear dynamics of baseband pulse propagation in a dusty plasma waveguide possesses essentially non-solitonic behaviour. Namely, the propagation of ion-sound pulses of finite amplitudes leads to an excitation of shock-like waves and, then, to the destruction of the pulses but not to emerging stable localized nonlinear structures.

Nonlinear transformation of seismic waves into ultra-low frequency atmospheric acoustic waves

A nonlinear mechanism of the transformation of low-frequency seismic waves into ultra-low frequency atmospheric acoustic waves is discussed. The spectrum of the seismic waves caused by the earthquake is wide but only ultra-low frequency acoustic waves reach the ionosphere. This process can be amplified due to the nonlinear interaction of low frequency waves and their transformation into ultra-low frequency acoustic wave at the difference frequency. It is shown that thus the efficiency of this transformation is high.

The role of flares, CMEs and CME shocks in the generation of solar energetic proton events

We examined solar energetic proton (SEP) events associated with intense Hα flares. We located these flares on the solar disk and obtained their distribution in heliographic longitude as well as their angular distance distribution with respect to the neutral lines corresponding to the heliospheric current sheet at 2.5R⊙. We found that the SEP-associated Hα flares tend to occur in active regions at the feet of those helmet streamers which form the heliomagnetic equator and are related to coronal mass ejections (CMEs) and CME shocks. We discuss the possible role of flares, CMEs and CME shocks in generating SEPs.