15
$\begingroup$

This effect is frequently discussed in the context of solar time series. In particular, it a relationship between soft x-ray (thermal emission) and hard x-ray (nonthermal emission) from the Sun.

$\endgroup$
14
$\begingroup$

The Neupert Effect describes the commonly observed phenomenon that hard X-rays occur predominantly during the rise phase of soft X-rays during a solar flare, as illustrated by the graph below:

Neupert Effect during a flare observed by Yohkoh

In the graph, the first peak is that of the hard X-rays, which you can see occurs during the rise of the other line which represents the soft X-rays.

Source:

| improve this answer | |
$\endgroup$
5
$\begingroup$

Following the previous answer stating that the HXR emission occurs during rise phase of the flare as evidenced by the full-Sun SXR flux observed i.e. by GOES in 1-8 Angstrom, I would add that the HXR maximum is typically observed during the strongest increase of the SXR flux, i.e., during d(flux_SXR)/dt = max.

| improve this answer | |
$\endgroup$
2
$\begingroup$

What's more, the Neupert effect is often stated that the hard X-rays look like the time derivative of the soft X-rays. The physical significance of that is it suggests that the presence of hard X-rays relates directly to the energization of soft X-ray gas. It supports the common model that hard X-rays are a byproduct of particle acceleration, and the accelerated particles deposit heat that gradually leaks out as soft X-rays.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.