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INTERVIEW
WITH DR. ADOLFO FIGUEROA-VIÑAS
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My name is Adolfo Figueroa-Viñas. I am
a Research Plasma Scientist at the NASA Goddard Space
Flight Center. I’ve been working in solar
plasma physics for the last 25 years.
Looking at the sun with the naked eye it seems, constant,
static and unchangeable. The only apparent changes
are associated with the position of the Sun in the
sky. Either with clouds or changes associated
with day and night. However, the Sun is more dynamical
and turbulent, and its effects on Earth are direct. The
Sun drives a cosmic analogue of clouds, magnetic storms,
precipitation, and radiation. These effects manifest
themselves as solar wind, magnetic clouds, radiation,
magnetic radiation, particles, charged particles, precipitation
and magnetic storms. Space Weather is a term
that we used to represent all these physical events;
how these physical events are controlled by the Sun;
how the Sun effects and influences the Earth and life
itself on the planet.
The Sun is like a huge thermonuclear reactor fusing
hydrogen with helium and generating intense magnetic
fields and producing plasma over a million degree temperature.
Plasma is a gas, also known as the fourth state of
matter, composed of protons, electrons and heavier
ions that interact collectively via electromagnetic
forces. Near the Sun’s surface, it looks like…plasma
looks like boiling water. Basically, you have
convective motion and the plasma bursts outside of
the surface into space. The constant streaming of that
plasma out into space is called solar wind. As the
solar wind stream through the interplanetary media
it first encounters the Earth's magnetic field and
forms a cavity around it, which is known as the magnetosphere.
This magnetic field of the Earth also serves as the
shielding that protects us from the radiation from
the Sun. Although only one percent of the solar
wind is able to penetrate the magnetosphere, the impact
of the Earth and Earth systems is very intense.
Sunspots and solar flares are like tornadoes and lightening
on Earth. They are localized and potent. Sunspots
are regions and areas of the Sun where there are very
intense magnetic fields; and these regions can be seen,
because they are cooler usually by three thousand Celsius
in comparison with the gases that surround it which
are about six thousand degrees Celsius. Solar flares,
on the other hand, are very intense bright spots on
the surface of the Sun. These are the regions where
the most intense radiation and particle precipitation
occur.
Perhaps, the most dramatic and important event from
the Earth’s perspective are the coronal mass
ejections, also known as CME’s. CME’s are
huge or gigantic eruptions of plasma from solar outer
atmosphere called corona. CME’s are the analogue
of hurricanes in the Earth’s atmosphere. The
corona is that part of the solar atmosphere that extends
into the solar wind at a plasma at a temperature of
about a million degrees Celsius. The temperature in
the corona is even higher than the surface of the Sun.
Therefore, this is one of the biggest mysteries in
solar physics. How is it that the atmosphere is hotter
than the surface of the Sun itself?
CME’s occur a few times a week to several times
a day depending on the solar activity. As the CME expands,
it becomes so huge that sometimes it’s probable
that it will hit our planet. Fortunately, our planet
has a protective shield, which is the magnetic field
and the magnetosphere. That will deflect the flow from
the CME around our planet. However…sometimes
particles are able to penetrate and they can flow out
the magnetic fields and go to the poles, the north
and south poles and produce magnetic storms and auroras.
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