Università Roma Tre

Roma Tre University - A.A. 2019-2020
Program of the course of "Physics of the Ionosphere and Magnetosphere"
prof. Carlo Scotto
Most of the topics are dealt in the book by G.W. Prölss ("Physics of the Earth's Space Environment", ed. Springer). Reference is made to the paragraphs of this book. The remaining topics are reported in the distributed Lesson Notes. The relevant detailed bibliography is shown in them.
Introduction: purpose of the course and presentation of the topics covered.

1. Notions of magneto-ionospheric plasma physics
Plasma frequency, Debye distance and Debye-Hückel potential, plasma conditions, free mean path, phase refraction index for radio waves in a plasma without collisions and in the absence of magnetic field, cold plasma (Lesson notes). (P. 232, § 7.3.1, § 7.3.2, § 7.3.3). Energy of the electromagnetic field (Lesson notes). Motion of electric charges in a magnetic field: gyration motion, the magnetic moment as an adiabatic invariant, motion where grad(B) is parallel to B, bounce motion (§ 5.3.1, § 5.3.2, pp. 220-228), gradient drift motion (§ 5.3.2, pp. 228-229), neutral shift drift, drift E x B and plasma conductivity in the absence of collisions, drift under the action of external forces (§ 5.3.1, § 5.3.2, § 5.3.3 pp. 219-233).

2. The interplanetary medium.
The solar corona and the solar wind (§ 6.1 and 6.1.1, pp. 278-282, including all the references). Large-scale solar wind structure and on the ecliptic plane (§ 6.1.6). The interplanetary magnetic field: observations and physical characteristics (§ 6.2.1, pp. 300-304). The heliosferic current sheet (§ 6.2.4). Segment structure of the polar component of B (§ 6.2.5). Alfven's theorem (Appendix A.14, pp.484-487).

3. Magnetosphere
The geomagnetic field near the Earth (§ 5.2). Curvature drift (p. 233). Total drift (p. 234-235). Composed motion of charge carriers (§ 5.3.4). Particle populations in the internal magnetosphere: radiation belts, ring current, plasmashere (§ 5.4).
The distant geomagnetic field: configuration and classification, currents on the diurnal side of the magnetopause, reflection of the particles and formation of the current, system of currents in the geomagnetic tail (§ 5.5). Particle population in the external magnetosphere: magnetotail plasma sheet, magnetotail lobe plasma, magnetospheric boundary layer (§ 5.6). Formation of bow shock and the magnetosheat (§ 6.4 introduction and § 6.4.1, pp. 325-328).

4. Ionosphere
Absorption processes, gas radiation attenuation, energy deposition in the upper atmosphere: Chapman function. Earth ionosphere: historical outline, vertical profile of electron density, ionospheric temperature, production and disappearance of ionization, ionospheric regions, electronic equilibrium, vertical profile of electron density in E region and in region F2 region (§ 3.2; introduction of chap 4, § 4.1, § 4.2, § 4.3). Ionosphere morphology: the cusps on the ionogram trace and the ionospheric regions (Lesson notes). Regular variations of the ionosphere: layers E and F1 (Lesson notes). Irregular variations of the ionosphere: F2 layer (Lesson notes). Sporadic E layer(Lesson notes). Simplified photochemical model for regions E and F: F1 layer (Lesson notes). Simplified photochemical model for region D (Lesson notes). Refraction index for radio waves with collisions and in the absence of a magnetic field; interpretation of the imaginary part of the refractive index: absorption ( Lesson notes). Solar flares and short waves fadeout (Lesson notes). Additional notes on the F1 layer (Lesson notes). Additional notes on layer E (Lesson notes).

5. Magnetoionic theory
Introduction. Constitutive equations for a cold plasma with collisions and in the presence of a magnetic field (Lesson notes). Refractive index for radio waves in the ionosphere, neglecting collisions and considering the Earth's magnetic field: Appleton-Hartree equation (Lesson notes). Continuity of nf in X = 1. The zeros of the collisionless Appleton-Hartree equation: longitudinal, transverse and general propagation case (Lesson notes). Polarization: continuity in X = 1 in the general case and in the case of longitudinal propagation. Polarization in case of longitudinal propagation: dependence on the sign of YL. Polarization in general conditions, for X = 1 (Lesson Notes). Refractive index for radio waves in the ionosphere, considering collisions and the earth's magnetic field. Mention upon the polarization in the collisional case. Curves of mi(X) with collisions: importance of the Booker rule (Lesson notes). Conditions of reflection and ionograms, ordinary, extraordinary trace. Ray Z (Lesson Notes). Examples of ionograms (Lesson notes).
As indicated in the lesson notes, the material of this teaching unit can be found at: Ratcliffe, J. A. (1959), The magneto-Ionic Theory and its Applications to the Ionosphere, Cambridge University Press.

6. Absorption and dissipation of solar wind energy
Topology of the high polar atmosphere (§ 7.1). Electric fields, and plasma convection (§ 7.2). Conductivity and currents in the polar ionosphere (§ 7.3). Polar auroras: energy dissipation of the auroral particles, origin of the auroral particles, diffuse and discrete aurora(§ 7. 4). Solar Wind Dynamo (§ 7.6.1), open magnetosphere (§ 7.6.2), plasma convection in the open magnetosphere (§ 7.6.3), open magnetosphere with tail (§ 7.6.4), mention upon the reconnection (part of § 7.6. 5) Birkeland currents in regions 1 and 2 (§ 7.6.6).

7. Geospheric storms
Magnetic storms: regular variation, equatorial electroject, magnetic activity at low, high and medium latitudes, geomagnetic indexes (§ 8.1). Magnetic substorms: growth and expansion phase, Alvfèn waves and their role (§ 8.3). Ionospheric storms: negative and positive storms (§ 8.5).

Per l' Anno Accademico 2019-2020:
1) G.W. Prölss "Physics of the Earth's Space Environment"
2) Lecture Notes