Solar wind disturbances caused by solar flares: Equatorial plane

Akasofu, S.‐I.; Hakamada, K.; Fry, Christopher

doi:10.1016/0032-0633(83)90018-1

Cited by 13 publications

(3 citation statements)

References 27 publications

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“…Examples of flares that occur at various angles to the shock observation locations are discussed later when we model the August 1972 events. This speed anisotropy also produces a shock surface shape that is similar to those generated by Akasofu et al [1983]. Equation (2) results in a simplified three-dimensional shock front speed profile (in the solar wind frame).…”

Section: Shock Front Shapementioning

confidence: 92%

A simplified model for timing the arrival of solar flare‐initiated shocks

Smart¹,

Shea²

1985

J. Geophys. Res.

121

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The solar flare‐initiated shock can be considered to be an initially driven shock that converts into a blast wave as it propagates through the interplanetary medium. In our simplified shock modeling, to estimate the time of the shock arrival at a specified position in space we assume that the shock is initially driven from the flare position at the velocity indicated by the type II solar radio burst. We assume the shock is driven until the initiating solar flare energy is somewhat expended. After this initially driven phase, the shock front then propagates with the characteristic speed expected of the shock front of a blast wave. In the interplanetary medium with its 1/r² density dependence, the blast wave shock front speed should be proportional to r−0.5. We find that this r−0.5 speed dependence is a general characteristic of the shock front speed when the speeds are determined in the solar wind reference frame. The blast wave “rides over” the preexisting solar wind so that the disturbance speed of the shock front at any instant of time is the speed of the shock front added vectorially to the solar wind speed. Application of these principles enables a consistent “timing” of solar flare‐initiated shock waves that is event independent. We show that this concept is consistent with the time position profile derived from the analysis of kilometric type II events that are associated with interplanetary shocks.

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Section: Shock Front Shapementioning

confidence: 92%

A simplified model for timing the arrival of solar flare‐initiated shocks

Smart¹,

Shea²

1985

J. Geophys. Res.

121

View full text Add to dashboard Cite

show abstract

“…1 o Introduction generated pfasma streams and coherent corotating plasma streams may be observed over large radial distances within the solar system (Burlaga ef al., 1980;Dryer, et al, 1982;Akasofu et al, 1983;Suess, ef al., 1984). During recurrent periods of solar activity, relatively orderly and coherent plasma streams spiral outward, corotating with the Sun.…”

mentioning

confidence: 99%

“…During recurrent periods of solar activity, relatively orderly and coherent plasma streams spiral outward, corotating with the Sun. Sporadic solar fluctuations such as strong flares or filament eruptions can produce bursts of outward propagating plasma streams which overtake the outward spiraling corotating stream, producing downstream field and plasma interactions which may seriously complicate the apparent signature of the original corotating stream (Akasofu et al, 1983). In addition, the leading edge of the propagating corotating stream is continuously interacting with the downstream solar wind plasma, such that a shock may form at the leading edge and evolve in structure, with both time and distance (Burhga, 1979) The interaction of these processes often results in complicated do~~nstream characteristics in the solar wind.…”

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confidence: 99%