Γεωμαγνητικές
αναστροφές:
αναστροφές:
Η προέλευση του μαγνητικού πεδίου της Γης
Geomagnetic Reversals and excursions:
The origin of
Earth’s magnetic field
Earth’s magnetic field
Palaeomagnetic
observations offer important insights into the origin of Earth’s interior, but
a detailed reconstruction of the underlying dynamics is not feasible. A
practical alternative is to construct a stochastic model for the time evolution
of the dipole field.
observations offer important insights into the origin of Earth’s interior, but
a detailed reconstruction of the underlying dynamics is not feasible. A
practical alternative is to construct a stochastic model for the time evolution
of the dipole field.
Slow changes
in the field are described by a deterministic (drift) term, whereas short-time
fluctuations are represented by a random (noise) term. Estimates for the drift
and noise terms can be recovered from a time series of variations in the axial
dipole moment over the past 2 million years. The results are used to predict a
number of statistical properties of the palaeomagnetic field, including the
average rates of magnetic reversals and excursions.
in the field are described by a deterministic (drift) term, whereas short-time
fluctuations are represented by a random (noise) term. Estimates for the drift
and noise terms can be recovered from a time series of variations in the axial
dipole moment over the past 2 million years. The results are used to predict a
number of statistical properties of the palaeomagnetic field, including the
average rates of magnetic reversals and excursions.
Dr. Buffet
will explain how a physical interpretation of the stochastic models suggests
that reversals and excursions are part of a continuum of time variations in
Earth’s magnetic field, arising from convective fluctuations in the core.
Relatively modest changes the amplitude of convective fluctuations can produce
large changes in reversal rates, including the well-known occurrence of superchrons
lasting longer than 10 million years.
will explain how a physical interpretation of the stochastic models suggests
that reversals and excursions are part of a continuum of time variations in
Earth’s magnetic field, arising from convective fluctuations in the core.
Relatively modest changes the amplitude of convective fluctuations can produce
large changes in reversal rates, including the well-known occurrence of superchrons
lasting longer than 10 million years.
ΔΕΙΤΕ την ομιλία:
ΔΙΑΒΑΣΤΕ:
NASA:
Η Τελευταία Πλήρης Αντιστροφή των Μαγνητικών Πόλων της Γης συνέβη πριν από 780.000
χρόνια – NASA: Earth’s Last Full Magnetic-Pole Reversal Occurred 780,000 Years Ago -“We Are Over Due”.
Η Τελευταία Πλήρης Αντιστροφή των Μαγνητικών Πόλων της Γης συνέβη πριν από 780.000
χρόνια – NASA: Earth’s Last Full Magnetic-Pole Reversal Occurred 780,000 Years Ago -“We Are Over Due”.
ΛΕΞΕΙΣ-ΚΛΕΙΔΙΑ: ΜΑΓΝΗΤΙΚΟ ΠΕΔΙΟ, ΜΑΓΝΗΤΙΣΜΟΣ, ΓΕΩΜΑΓΝΗΤΙΣΜΟΣ, ΠΟΛΟΙ, ΜΑΓΝΗΤΙΚΟΣ ΠΟΛΟΣ, ΓΗ, ΝΑΣΑ
